The utility model provides a laser particle size analysis system, which comprises a beaker, a laser particle size analyzer, a liquid inlet pipeline, a liquid drain pipeline, a waste liquid pipeline and a waste liquid recovery part, wherein the first end of the liquid inlet pipeline is communicated with the beaker, and the second end of the liquid inlet pipeline is communicated with a liquid inlet of the laser particle size analyzer; the first end of the liquid drain pipeline is communicated with the beaker, and the second end of the liquid drain pipeline is communicated with a liquid outlet of the laser particle size analyzer; the first end of the waste liquid pipeline is communicated with the liquid drain pipeline; the second end of the waste liquid pipeline is communicated with the waste liquid recovery part. According to the system, the waste liquid pipeline and the waste liquid recovery part are independently arranged, and then waste liquid flowing back to the beaker through the waste liquid pipeline can be drained through the waste liquid pipeline, so that the waste liquid can be drained in no need of disassembling the liquid inlet pipeline and the liquid drain pipeline and in no need of moving the beaker, the complexity in operation is effectively lowered, the labor intensity of a worker is reduced, and the probability of damage to the liquid inlet pipeline and the liquid drain pipeline is lowered.