A goal of a present work is to increase information value of nonintrusive liquid and gas flow investigation via laser sheet plane. In application to based on particles flow investigations methods a correction method was developed in order to take into account a difference between particles’ velocity and gas velocity. An original criterion of two-phase flow nonuniform velocity fields determination is proposed. Pressure, temperature and density fields’ determination algorithms via particles’ velocity fields’ processing are developed. Results of images processing were obtained. A panoramic method of particles size distribution of a polydisperse flow in a laser sheet plane is proposed. Original methods of data inverse problems (of flow parameters determination via optical measuring) were developed. Results of stability of a solution are given. Results of experimental two-phase flow investigations are given.