The utility model discloses an aerosol particle optical detecting system, comprising a dual pipe core laser emitter, a scattered light path unit, a first photoelectric detection unit, an ultraviolet laser emitter, an ultraviolet light path unit, a second photoelectric detection unit, a first light concentration device, a second light concentration device, a nozzle and a light extinction device. As the aerosol particle optical detecting system adopts the dual pipe core laser emitter which can directly generate two beams of laser, single beam laser does not need to be split by adopting the wave plate, calcite and other optical devices of the prior art, which reduces the number of the components forming the system, simplifies and compacts the structure, and also ensures that the light path adjustment is more convenient.