This article analyses the relationship between robotisation, quality of employment and workers' happiness by using the 2018 data of the China Labor-force Dynamics Survey. The study reveals that robotisation has an impact on workers' happiness and that quality of employment has a related moderating effect. Robotisation tends to increase retained workers' income and improves labour security at the expense of laid-off workers, resulting in increased working hours and reduced work autonomy. In one perspective, workers are controlled and alienated by robotisation. Factories however stabilise workers' motivation by increasing workers' wages and improving their labour security. The effect of robotisation on workers' happiness is enhanced by the increase in wage income but limited by the increase in working hours. The influence of robotisation on different skilled workers is heterogeneous; specifically, the effect on low-skilled workers is even greater than the average. Therefore, dealing with the dynamic changes of the relationship among the state, capital and workers is of paramount importance in order to realise the harmonious development of man–machine.