How people allocate study time? Agenda-Based Regulation proposed by Ariel, Dunlosky and Bailey(2009), assumes that learners construct and execute agendas which play a core role in study time allocation. The present research was conducted to further explore the internal mechanism of the construction of agendas by examining the effects of item difficulty and item reward on self-paced study time. Experiment 1a and 1b were conducted to exam the effects of item difficulty and item reward on self-paced study time respectively. There were 20 senior high school students taking part in Experiment 1a. Participants were asked to learn 30 noun-noun paired associates in Chinese. On one trail, the cues of three pairs were presented on computer screen and the targets of pairs would be display when they clicked on the pairs. One of the item pairs was easy, one was of medium difficulty, and one was difficult. The study time allowed for each trial was 10s. The results showed that participants devoted more of their study time to the difficult items than the medium and easy items. There were 18 senior high school students taking part in Experiment 1b. Participants were asked to learn 27 noun-noun paired associates in Chinese.The rewards of learning items were randomly assigned to the three pairs of each triad. Each triad was made up of one pair with 5 points, one pair with 3 points and one with 1 point. The same procedure uesd in Expeiment 1a were used in Experiment 1b. The results showed that participants allocated more study time to 5-point items than 3-point and 1-point items. The purpose of Experiment 2 was to investigate whether there existed a trade-off process when learners developped their agenders by manipulating the item difficulty and item rewared. We conducted two kinds of learning condictions, which were manipulating within subjects. This experiment found that participants spent more study time on 1-point difficult items and 5-point medium items than 5-point easy items in the “5-point medium item” condiction, and allocated more study time on 1-point difficult items than 1-point medium items and 5-point easy items in the “5-point medium item” condiction. The results indicated that there existed a trade-off process in the self-paces study for learners, which was based on the principle of achieving task goals as efficiently as possible. These results were in accordance with the agenda-based regulation model (ABR) regarding the study time allocaion. Not only the item difficulty but also the item reward could affect the agenda construction and execution. Further more, These findings provided more evidence for the internal mechanism of the agenda construction of ABR framework (in terms of using the region of proximal learning) .