The invention provides an RV reducer parametrization design modeling method comprising a first step of establishing a parametrization data flow model and a second step of establishing a parametrization design system. The first step comprises the sub-steps of: performing module division and series division on a product structure; dividing parts into a first-stage speed reduction part, a second-stage speed reduction part and an output part according to the working principles of the product; dividing parameters into different levels according to structural characteristics, and analyzing various feature sizes to determine the drive size and the driven size, wherein the drive size is the design target size; then optimizing the design flow of the reducer and dividing the whole design flow into four stages, which are an initial parameter input stage, a product initial design stage, a product optimization design stage and a product detail design stage; finally realizing the delivery of input and output information of design feature parameters of each part through design and cooperation relationships. The parametrization design system comprises a parametrization design preprocessing module and a result postprocessing module.