The invention provides a measuring system for an atmospheric ice nucleus activation rate, comprising an air compressor, a compression tank, a first drying device, a filtering device, a Venturi tube, asecond drying device, a DMA separation device, a diffusion cloud chamber, an optical counter and an air pump which are successively connected, wherein the Venturi tube is connected to a chemical solution bottle at a minimum diameter position in order to suck a chemical solution into the Venturi tube, mix the chemical solution with the clean air, and dry the chemical solution to form particles; the DMA separation device is configured to separate out particles with certain particle sizes; the separated particles enter the diffusion cloud chamber and are activated into ice nuclei counted by a photoelectric counter. The system can measure the nucleation rates of atmospheric particles with different compositions and different particle sizes activated into atmospheric ice nuclei, and provides apractical measurement system and method for the subsequent study of the nucleation mechanism of the atmospheric ice nuclei.