Protein quantitation is often involved in the analysis of biochemistry and other life sciences. It is also the most common method in biological science, food inspection, clinical inspection, diagnosis of disease and quality inspection. There are five common ones, which are Bradford method, Bradford spot test, Coomassie spot test, ultraviolet spectrophotometric detection and BCA method. The protein electrophoresis reagents are developed based on Commassie blue stain (also called Bradford method) and BCA method. Coomassie blue staining was a method to measure protein staining established by Bradford in 1976. BCA method is a widely used method for protein concentration determination at present, which is characterized by high sensitivity and wide linear range.