Abstract:A double hoist hydraulic system of diaphragm wall grab crane was introduced.A mathematic model was built for the double hoist synchronous system.Synchronous control strategy of proportional integral derivation(PID) with masterslave mode was adopted,and an online adaptive genetic algorithms (GA) was employed to optimize the parameter of PID.The simulation results show that the proposed algorithm has better control performance than traditional GA.Field test data indicate that there are good synchronizing effects by applying the proposed control strategy,and the synchronization precision can be controlled within±0.35°,which can meet the working requirements in engineering,and it is more capable of improving precision of synchronism driving than the PID control with traditional GA.