Background: In the Chinese educational system, there has been an ongoing debate between using examination- or quality-oriented education. The Chinese concept of psychological "suzhi" was proposed based on quality-oriented education, and a positive link between psychological "suzhi" and academic achievement was found by cross-sectional studies; however, studies examining their longitudinal relationship are still lacking. Aims: To examine the longitudinal trajectories of Chinese adolescents' academic achievement and the longitudinal effects of psychological "suzhi" on academic achievement trajectories. Sample: Participants were 3,587 adolescents (M[subscript age] = 14.85 years, 51.1% male) in grades 7 and 10, from 10 secondary schools in southwest China. Method: A 2-year (four-wave) longitudinal study was conducted, and growth mixture models were used to analyse the data. Results and conclusions: Four distinct developmental trajectories of academic achievement were identified (i.e., high-positive growth, middle-negative growth, low-stable, and lowest-stable) that were significantly predicted by different levels of psychological "suzhi," particularly the dimension of "cognitive quality." "Cognitive quality" was strongly associated with the initial academic achievement values in the high-positive growth group and linked to achievement rate (decreasing) in the middle-negative growth group. However, "individuality quality" and "adaptability quality" had a buffering effect on the rate of achievement decreasing in the middle-negative growth group. This study not only highlighted the promotive role of high "cognitive quality" on high levels of achievement (static) but also indicated the protective role of non-cognitive factors (i.e., "individuality" and "adaptability") against a decreasing rate of academic achievement (dynamic).