In this paper, the gas-liquid two-phase flow of liquid-gas jet device was simulated. The movements of flow field and flow mechanism are pointed out, the process of bubble forming in which the second phase was sheared, torn and mixed was analyzed. Different parameters including velocity field, pressure field and volume fraction of liquid, turbulent kinetic energy and turbulent dissipation rate of mixing chamber, throat and diffuser indifferent instantaneous were investigated based on numerical calculation. The results show that the flow field is highly unstable, and the flow at 7s is more violent than 51s, the large vortical structures developed in the mixing chamber, which can influence the nozzle performance of liquid-gas jet device, and consume kinetic energy. The primary phase is mainly distributed in the lower of mixing chamber, the upper of throat, outlet section and near the inner wall of diffuser.