The gas–liquid phase mass transfer coefficient of entrained flow reactor is studied in the paper. The liquid solvent is atomized into the entrained flow reactor after going through a type of pressure nozzle used in the experiment. The isometric decompression technique is used to investigate the mass transfer coefficient of the entrained flow reactor in seven different gas–liquid systems. The effect on mass transfer coefficient of Re and We number of droplet is sufficiently discussed. A mass transfer coefficient correlation model is proposed and the parameters in the model are obtained by nonlinear regression method. The residual shows that the model values are in good agreement with the experiment values.