This paper contributes to the literature on wellbeing research by showing the distinct impacts of inter- and intra- generational social mobility on subjective wellbeing in mainland China. Based on the China General Social Surveys of 2006, we used diagonal reference modelling and other regression methods to assess the effects of social mobility on wellbeing. We found that wellbeing was associated with changes in class positions. In both inter- and intra- generational mobility trajectories, moving upward into a higher position was beneficial for people’s wellbeing whereas different consequences were found for downward mobility: in the case of intergenerational mobility, downward mobility into the manual class did not have a marked effect on people’s wellbeing as the downwardly mobile from privileged backgrounds held the prospect of counter-mobility at early career stages and inherited valuable resources; but downward mobility in one’s own career life was rather detrimental to subjective wellbeing, as the downwardly mobile had to bear not only the material disadvantages found in the lower position, but also the psychological effects ensuing from the downward trajectory. We conclude that while those experiencing downward intergenerational mobility may resort to family advantages to help maintain their wellbeing levels, a similar trajectory in one’s own career life may have a direct negative consequence.