The expression of therapeutic protein drugs (such as monoclonal antibodies) in Chinese hamster ovary (CHO) cell culture is a relatively inexpensive and effective method. However, these products are prone to residual contamination of host cell DNA during production and purification processes. The pharmacopoeia has quantitative requirements for the host cell DNA of protein drugs, and biopharmaceutical companies can also use online detection methods to confirm the rationality and effectiveness of pure chemical Yida. The fluorescence quantitative PCR method is becoming the gold standard for residual host cell DNA detection, which can detect sub picogram amounts of residual DNA in Chinese hamster ovary (CHO) cell lines within 5 hours while maintaining excellent specificity and sensitivity. This kit adopts the Taqman probe method for specific design and a strong anti inhibition PCR reaction system to ensure the authenticity and effectiveness of experimental results.