This paper proposes the Hartmann ray tracing method to measure the gas-phase parameters of the gas-liquid two-phase flow,and conducts theoretical and experimental research.First,the Hartmann template is used to obtain the array beam,and the propagation process of the light in the gas-liquid two-phase flow is simulated and traced to study the relationship between the emitted light and the bubble size and position in the two-phase flow.Second,the BP neural network model is established to achieve accurate inversion of bubble parameters.The simulation results show that the relative error of bubble positioning is within 7%,and the relative error of bubble size is within ±4%.On this basis,an experimental system is built to simulate the process of a single gas phase passing through the pipeline with transparent particles of known size settling in a vertical pipeline.Experimental research is carried out.The results show that the relative error of bubble size can be controlled within ±6%.