The invention discloses a preparation method of soluble polymers prepared by compound enzyme modified whey protein and belongs to the technical field of protein preparations. The invention aims to solve the technical problems that viscosity changes of existing enzyme modification induced gel are not obvious or slow in growth speed with the prolonging of the refrigerating time and gelling ability is poor, so that the gel is not suitable for application. The method comprises the following steps: whey protein solution is stirred and pre-heated, protease is added for hydrolyzing, after being hydrolyzed, the hydrolyzed whey protein is sealed with a preservation film, the sealed hydrolyzed whey protein is heated instantly to enable the enzymes to be inactivated, the heated hydrolyzed whey protein is cooled with water to 50 DEG C, 5.0 U/g of mTGase is added, the mixture is reacted for 1 h, the mixture is heated to 85 DEG C for 5 min to enable the enzyme to be inactivated, and the obtained sample is cooled to a room temperature to obtain the soluble polymers. The whey protein soluble polymers produced by the method are transparent in appearance, suitable in viscosity, easy to apply, stable and high in gel properties.