Occupational mobility represents a crucial form of social mobility and a key process for enhancing the allocation level of labor factors. Adopting a task-based analytical framework, this article characterizes heterogeneous occupational mobility through inter-occupational task distances and empirically examines the impact of occupational mobility on wage growth using data from the China Labor-Force Dynamic Survey (CLDS) and China Family Panel Studies (CFPS). Robust evidence reveals that increased task distance between occupations significantly inhibits wage growth, confirming the wage penalty effect of occupational mobility. The wage penalty effects are larger for workers aged 40 to 60, with non-agricultural hukou, senior high school education, or with proactive job transition. Wage growth can be observed 3-7 years after job transitions. While cross-task-group mobility exacerbates this penalty, transitioning into non-routine task groups or exiting routine manual task groups counteracts the negative effect. Furthermore, accumulating general human capital effectively buffers the wage penalty effect induced by occupational mobility. This study not only illuminates the "black box" of occupational mobility's wage effects but also provides evidence for optimizing labor market institutions and advancing high-quality employment.