Preparation of Coomassie Brilliant Blue reagent: 100mg of Coomassie Brilliant Blue is dissolved in 50mL of 95% ethanol, diluted with water to 1000mL, and filtered for use. The final concentration of the reagent was 0.1 g / L card Mas Blue Blue G-50, 4.7% ethanol, 8.5% phosphoric acid. Standard protein solution: The stock 5mg / mL bovine serum albumin was formulated into 50ug / mL. Drawing of protein standard curve: Use a pipette to accurately measure 50mL / 0mL, 0.mL, 0.4mL, 0.6mL, 0.8mL, 1.0mL of standard protein solution, and make up to 1.0mL with water to make the final concentration 0ug / mL mL, 10ug / mL, 0ug / mL, 30ug / mL, 40ug / mL, 50ug / mL standard protein solution.