A multi-target optimization method for a main bearing of an RV speed reducer comprises the steps of analyzing an external loading condition of the main bearing, building a quasi-static model of the main bearing of the RV speed reducer, and outputting target functions to be angular rigidity, a friction moment and an axial rated dynamic load of the main bearing of the RV speed reducer; randomly generating an initial population, calculating three optimization target function values of each individual by the model, performing non-dominated sorting, calculating a congestion distance, performing selection, heuristic crossover and Gaussian mutation to generate a new population based on a binary system tournament, and calculating a target function of each individual; and combining a parent population and the new population to form a big population, extracting the best individual to be used as a population entering next iteration, removing a repeated individual of the population after combination, detecting whether a current algebra reaches a set algebra or not, and outputting an optimization result. By the multi-target optimization method, a group of pareto-optimal design parameters which can be reference data for a designer can be acquired, whether the current design is a theoretical non-dominated solution can also be determined, and meanwhile, the algorithm efficiency is improved.