Researches on Negation are an essential part for the exploring of language understanding. Various researches on Negation are frequently related to the processing and mechanism. Psychologists have proposed some convincing theories, among which propositional theory and experiential-simulations view are especially well known. Double negative sentence is a very special negative sentence, for its sentence structure is not in concord with its semantic representation. It expresses an affirmative meaning with a negative form. Using sentence-picture-verification paradigm and the isolated sentences with contradictory redicates and pictures for the experimental materials, this research aimed to investigate the influence upon sentence processing which is made by two factors: the processing of double negative words and the inconsistence between the sentence structure and the semantic representation. This research offered new experimental evidence for propositional theory and experiential-simulations view, by designing two behavioral experiments. Experiment 1 used imperative sentences to examine the processing of double negative words under different modes of sentence presentation. At the same time it also investigated the differences among three kinds of sentences. The experiment used three factors mixed design. Setence presentation is a between-subjects factor and other two variables, including sentence types and sentence-figure matching relationships, are within-subjects factors. Using sentence-picture-verification paradigm, with isolated sentences appearing before pictures, this experiment demanded the participants to judge whether the pictures are consistent with the semantic representation. Stimulus presention and the recording of behavioral data (reaction time and accuracy) were controlled by E-prime 1.1. The main results were as follows: a main effect of sentence presentation emerged, that is, participants reacted more quickly when the sentences appeared as a whole than when the sentences appeared part by part. This didn’t conform to propositional theory. In addition, an interaction between sentence types and matching relationship was observed in the early state of understanding (250ms). Affirmative sentences and double negative sentences reached the match effect, the advantaged effect of actual state. This didn’t conform to two-step-simulation hypothesis. Experiment 2 used rhetorical questions to observe the differences among the processings of three kinds of sentences with different modes of sentence presentation. Meanwhile, it also investigated the influence made by the discord of the sentence structure and the semantic meaning upon the sentence processing. The procedure and design are the same as Experiment 1. However, the experimental materials were changed by rhetorical questions. The result showed that in the early state of understanding (250ms), negative rhetorical questions had match effect, while affirmative rhetorical questions and double negative rhetorical questions didn’t. It implied that the processing of negative rhetorical questions is the same as affirmative imperative sentences and double negative imperative sentences which are one-step stimulation. While unlike affirmative imperative sentences and double negative imperative sentences, the processing of affirmative rhetorical questions and double negative rhetorical questions are not one-step stimulation. When the sentence structures are inconsistent with semantic meaning, readers are more influenced by the sentence semantic. From the results, three conclusions of this research were drawn: (1) The processing of double negative words was global, which was in discord with propositional theory. (2) During the early state of understanding (250ms), the processing of double negative imperative sentences and negative rhetorical questions are the same, which is one-step simulation, representing the actual state of affairs. This didn’t conform to two-step-simulation hypothesis. (3) When the sentence structures are inconsistent with semantic meaning, readers are more influenced by the sentence semantic. In sum, our results sugest that, in the explanations of the processing of double negative mechanism, propositional theory emphasized the sentences structure, ignoring the semantic meaning while two-step-simulation hypothesis based on experiential-simulations view emphasized the semantic meaning, ignoring the sentences structure. Therefore, these two explanations were reasonable and unilateral at the same time.