Photonic networkonchip (PNoC) has been a new trend for next generation networkonchip development. Microring resonator is the key component in PNoC. However, microring resonators are sensitive to process variation and prone to fault. Therefore, how to tolerant the microring resonator fault due to process variation is a key problem to improve the reliability of PNoC. Aiming at this problem, a finegrain based tolerance method of microring resonator process variation is proposed. Firstly, the model of microring resonator process variation was built; then, a tolerance method of microring resonator process variation based on salp swarm algorithm was proposed; finally, the tolerance of a multistrategy redundant microring resonator was conducted. The experiment results indicate that compared with integer linear programming method, the proposed approach increases the bandwidth by 21% and decreases the trimming power consumption by 667%, which proves the effectiveness of the proposed approach.