A series of studies have revealed that automatically cognitive and emotional aspects of mental illness stigma, as assessed by Implicit Association Test (IAT) or Brief Implicit Association Test (BIAT). But there is no concept about implicit stigma toward mental illness in the past research. On the basis of previous stigma studies, and combing the Affect-Behavior-Cognition of Attitudes, the present study conceptualize the implicit stigma toward mental illness is the introspectively (or inaccurately) unidentified traces about mental illness, which unconsciously regulate the individual’s belief and reaction of people with mental illness; these traces include automatically negative cognition, passive emotion and discrimination tendency. However, because most of researches have been conducted with the negative cognitive and emotional aspects of implicit stigma, very little has been done to discover the behavioral tendency of implicit stigma. Otherwise, because it needs complementary pares of concepts and attributes, both IAT and BIAT are limits to measuring the strength of evaluative association with a single attitude objects, while mental illness is no natural complementary pairs. The purpose of this study was to examine the component of implicit stigma toward mental illness and implicit stigma among Chinese students, using standard attributes stimuli and Single Category Implicit Association Test (SC-IAT). A sample of 61 college students was recruited in the present study. According to the concept of implicit stigma toward mental illness, three independent SC-IATs, including cognitive evaluation SC-IAT, emotional ration SC-IAT and behavioral reaction SC-IAT, were used to measure implicit stigma toward mental illness. The results showed that: (1) In the three independent and total SC-IATs, the automatic association between mental illness and negative words was closer relative to positive words; (2) Implicit effect of all the SC-IATs were significant; (3) 65.57% of respondents had significant implicit stigma, indicating negative implicit attitudes against people with mental illness; (4) The results provided initial evidence for the reliability and validity of the SC-IATs as measure of implicit stigma against mental illness. Finding indicates that respondents have significant implicit effect, inclining to mental illness in contact with the negative words; that the developed SC-IAT measuring the implicit stigma is reliable and valid; that the components of ISMI include automatically negative cognition, emotion and discrimination tendency.