Proportion-integral-diﬀerential control is one of the most commonly-used control algorithms in reality. However, it often fails to get great performance on nonlinear systems. The purpose of this work is to achieve high tracking performance of a two-link robot. This paper proposed a repetitive control law based on sliding mode control. Stability and robustness conditions were proven. Then experiments were carried out. The results showed that the average absolute error can be less than 0.01 rad. The research is important and useful in reality because the proposed control law does not require exact system parameters.