The present invention provides a preparation method of testicular specific protein 50 humanized single-chain antibody. Said invention utilizes phage antibody presentation technique and adopts the following steps: using human testicular specific protein 50 as target antigen, utilizing immunoaffinity screening process to screen the recombinant phage human antibody variable region gene library, separating and cloning TSP 50 specific single-chain antibody gene AI,AII and C8, then respectively inserting single-chain antibody gene AI, AII and C8 into prokaryotic expression vector PelB, transforming Rosetta microphyte, utilizing IPTG to induce and express exogenous protein, after the thallus is cracked, ulitizing Ni-NTA column affinity chromatography to obtain purified single-chain antibody, utilizing ELISA method to judge that it can be specifically combined with TSP 50 holoprotein and 50 peptide, and using gene engineering measure to massively express said hamonized single-chain antibody. Said invention also discloses application of the testicular specific protein 50 humanized single-chain antibody for diagnosing and curing the diseases of female mammary carcinoma, etc. related to TSP 50.