<p><b>OBJECTIVE</b>To learn the dietary fat intake behavior status and influencing psychological factors in teenagers.</p><p><b>METHODS</b>According to the multi-stage stratified cluster sampling method, students were recruited from middle and high schools in Hangzhou, Wuhan and Xi'an from March to May, 2012. Chinese version of adolescent dietary fat intake behavior of psychological measurement scales was utilized in field investigations with 3 448 effective questionnaires. Under the transtheoretical model, the status quo of teenagers fat intake behavior was analyzed and it shows the relationship between stages and psychological variables, including strategy of change, decision balance and self-efficacy.</p><p><b>RESULTS</b>In the 3 448 participants, the proportion of girls were 52.4% (1 806/3 448) and boys were 47.6% (1 642/3 448), while the mean age was (14.85 ± 1.46). There are significant differences among distributed stages of behavior change, grouped by gender, grade and region (χ(2) values were 33.59, 20.53, 27.92, P < 0.001). In different gender groups, the number of boys in precontemplation came to the first and accounted for 24.2% (438/1 806), and the number of girls were more in contemplation and preparation stage, which accounted for 49.5% (813/1 642), and it was the least both in the action stage with the ratio 12.1% (218/1 806) and 14.7% (241/1 642) respectively; in different grade groups, the numbers of student in middle school and high school were the largest in contemplation and precontemplation stage, accounted for 24.9% (494/1 986) and 23.4% (343/1 462); and among different regions, the proportion in precontemplation, contemplation and preparation stage was not a few, and this ratio in Hangzhou, Wuhan, Xi'an area was 70.6% (801/1 135), 61.7% (649/1 052) and 68.8% (867/1 261), respectively. The number in action stage was the least of all, which were 144, 147, 168, respectively. Ordinal logistic mode showed that the four variables, including the scores of process of change, decision balance (pros), decision balance (cons) and self-efficacy, were factors which significantly affected the stages of behavior change, which showed a significant difference (F values were 155.12, 19.86, 44.59, 94.27, P < 0.001) in different stages. From precontemplation stage to action stage, the score of the process of change, decision balance (pros) and self-efficacy showed an upward trend, and achieved the highest score in the action stage (from 32.6 ± 12.8, 8.4 ± 2.9, 19.7 ± 6.9 to 48.4 ± 12.6, 10.1 ± 2.5, 25.9 ± 6.9, respectively); contrarily, the decision balance (cons) decreased with the development of behavioral stage (from 14.7 ± 4.4 to 12.2 ± 3.9). Post hoc comparison also found that the score of process of change, decision balance (pros) and self-efficacy after action stages were higher than those before action, while the score of decisional balance (cons) in the precontemplation stage was higher than that in the other 4 stages.</p><p><b>CONCLUSION</b>Fat intake behavior in teenagers showed different stages, whose psychological factors had significant influences, with decision balance (pros) hindered the progress of stages of behavior change, while other three factors played a positive role.</p>