The work aims to improve the effect of atomization, and select the optimal components of spraying liquid during the film forming process of the vegetable composite paper. The apparent viscosity of 30 groups of soybean protein spraying liquid was measured by Anton advanced viscosimeter, and the analysis software was used to carry out quadratic multiple regression fitting of each test result to get the optimal regression equation. According to the regression equation, the 3D response surface and contour maps were made. With the increase of the soybean protein concentration, its apparent viscosity gradually increased, while the CMC concentration had no obvious effect on the apparent viscosity. Based on the three-dimensional response surface and contour maps made, the impact significance of soybean protein concentration and CMC concentration on the surface mean diameter could be seen intuitively. With the increase of soybean protein concentration, the spray particle size increased gradually. With the increase of CMC concentration, the spray particle size decreased first and then increased. The effect of soybean protein concentration was more significant. The study on the effect of soybean protein liquid components on the apparent viscosity and particle size provides data reference for the uniform consistency of vegetable paper in the later period.