The invention discloses a preparation process of a high-
corrosion-inhibition 
cleaning agent used for a motor vehicle 
water circulation system. 
Gelatin is dissolved in redistilled water, a 
ferrous chloride solution and a 
hydrogen peroxide solution are added, stirring is carried out, a 
sodium hydroxide solution is added dropwise, and reacting is carried out for several hours in a boiling water bathto obtain nano-scale magnetic 
gelatin particles; 
cellulase is added, oscillating is carried out for several hours at the 
room temperature, the redistilled water is used for washing till no 
enzyme protein is washed out, so that the magnetic 
immobilized cellulase is obtained; then a certain amount of 
plant straw is taken and is subjected to crushing, then the quantitative water and magnetic 
immobilized cellulase are added, standing is carried out for several hours after stirring, and pressure 
filtration is carried out to remove residues to obtain a 
straw extracting solution; and the 
straw extracting solution, an organic cosolvent, a surfactant and a defoaming agent are added into a reaction kettle to be stirred and mixed to obtain the 
cleaning agent. According to the process, a 
crop straw extract is used as a main 
raw material, so that the source is rich, the 
process operation is simple, and the cost is low; and one-time and quick clearing under the conditions of multiple types of material and multiple types of 
dirt can be achieved, and the environment is not polluted.