The causes of transient flow in large-flow hydraulic system pipeline were analyzed based on the phenomenon of return pipe damage in super-large diameter mud water shield crusher.According to the field test data,the theoretical analysis was carried out.For the problem of transient flow impact on the return pipeline at the start and stop of the crushing cylinder,three kinds of methods to prevent transient flow hazard for super-large flow pipeline were put forward and tested respectively,including improving pressure capacity of the pipeline,installing return check valve and installing accumulator in the pipeline.And the experimental research was carried out respectively.The test results show that installing an accumulator in the return pipeline can effectively reduce the peak pressure impact in the transient flow pipeline and prevent the damage to pipeline,which provides reference for the design of hydraulic system of super-large construction machinery.