Although learning motivation (intention to learn) and use of learning strategies (goal-directed behavior) are critical aspects of learning processes, researchers of self-regulated learning have recently begun to give greater attention to how action control processes mediate the road from learning intention to goal attainment. According to action-control theory, goal-directed activity should be divided into the predecisional and postdecisional phases. The action control plays a mediating role between the aforementioned two phases. This study was an attempt to test a structural model of the mediating role of action control between the predecisional and postdecisional phases based on recent action-control theory by using structural equation modeling with the LISREL computer program. Furthermore, the mediating effects of action control between the intention to learn and goal-directed behavior on high and low learning adaptation students were compared. Subjects were 492 students (49% males) from ten junior and senior high schools in Taiwan area. The results of this study are as follows: (a) the theoretical model fit the observed data well and the study supported recent results of research on action-control theory, (b) the action control maintained the intention to learn, supported goal-directed behavior and increased the effect of learning motivation on learning strategies, and (c) the students with high learning adaptation exhibited greater mediating effects of action control on learning processes than those with low learning adaptation. Implications for theory, practice and research are discussed.