This paper aims to study the sprayability of soybean protein solution at different concentrations, attempting to obtain a uniform soybean protein film and provide a data reference for the selection of a suitable concentration of soybean protein solution for later mulching. The sprayability is judged based on the discontinuity of the PIV velocity field image. Under certain conditions of spraying parameters, the electronic pulse nozzle is used to spray different concentrations of soybean protein solution, and the PIV technology is used to measure the speed field image of the sprayed atomized particles of the soybean protein solution, and then the image is processed to qualitatively and quantitatively analyze the sprayability of the soybean protein solution of different concentrations of soybean protein. Under the condition of constant spraying parameters, when the concentration of the soybean protein liquid is low, the atomization characteristics are better and the sprayability is good; with the increase of the concentration, the particle velocity field of the soybean protein solution gradually shrinks, and the sprayability becomes worse. When the concentration is high (the mass fraction is 9.73%), the particle velocity field has discontinuous areas, no continuous and complete fan-shaped surface is formed, and the velocity curve of the radial distance on the cross-section line is discontinuous. Therefore, when the mass fraction of soybean protein solution is 9.73%, the sprayability is poor. The results show that the method of judging the sprayability based on the PIV velocity field image can provide a powerful reference for obtaining a uniform soybean protein film.