The kit uses a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) to assay the level of Human Epididymis protein 4(HE4) in samples. Add Epididymis protein 4(HE4) to monoclonal antibody Enzyme well which is pre-coated with Human Epididymis protein 4(HE4)monoclonal antibody, incubation; then, add Epididymis protein 4(HE4)antibodies labeled with biotin, and combined with Streptavidin-HRP to form immune complex; then carry out incubation and washing again to remove the uncombined enzyme. Then add Chromogen Solution A, B, the color of the liquid changes into the blue, And at the effect of acid, the color finally becomes yellow. The chroma of color and the concentration of the Human Substance Epididymis protein 4(HE4) of sample were positively correlated.