In this paper, a particle size measurement method based on continuous transmission extinction spectral is proposed. Based on Mie scattering theory and artificial bee colony algorithm for particle size inversion. The results show that the relative root-mean-square error (RRMSE) of particle volume frequency distribution curve is as low as 0.08% for unimodal distribution, and the RRMSE of particle volume frequency distribution curve is as low as 3.49% for bimodal distribution. Comparative experiments are conducted with the standard polystyrene latex particles numbered GBW120134, GBW120024 and GBW120041. The results show that the relative error of D50 particle size is within 10% for unimodal distribution, and the relative error of D50 particle size is within 20% for bimodal distribution.