Hydrogen peroxide (H₂O₂) is widely used in the food industry, environmental monitoring and analysis, fuel cell, clinical diagnosis and other fields. Hydrogen peroxide is not only a biomarker of severe diseases but also an important food additive. In terms of food safety and human health, it is of great significance to construct a simple, rapid and sensitive detection method. Colorimetric method is widely concerned because of its advantages such as easy operation, low cost and visualization of detection results. The enzyme commonly used in colorimetric method is horseradish peroxidase (HRP). However, natural enzymes are easy to deactivate, have high production costs and have poor stability. Nanoenzyme overcomes the disadvantage of HRP’s easy inactivation. However, some nanoenzymes are complex in synthesis, need to be characterized, and have poor water solubility and have low catalytic activity. Compared with HRP and nanoenzyme, copper ion (Ⅱ) with peroxidase-like properties has the characteristics of high sensitivity and does not need complex synthesis, is easy to obtain, easy to store, without modification can be directly used, simple operation and low analysis cost, etc. Copper ion (Ⅱ) can catalyze hydrogen peroxide to generate hydroxyl radicals and oxidize 3,3’,5,5’-tetramethyl benzidine (TMB) to produce the oxidation state TMB, which makes the color in the solution gradually change from colorless to blue, thus producing light signals that can be recognized by the naked eye and detected by ultraviolet spectrophotometer. Based on the above principles, a fast colorimetry sensor based on hydrogen peroxide was constructed and applied to detect tremella samples. The effects of hydrogen peroxide concentration, pH value, temperature and other factors on the absorbance were investigated. The pH value of the buffer solution was 3.0, the temperature was 40 ℃, the concentration of TMB and Cu(Ⅱ) was 6.0×10^-4 and 4.0×10^-3 mol·L^-1, respectively, and the reaction time was 20 min. Under the optimal conditions, the concentration of hydrogen peroxide had a good linear relationship with the absorbance of the system, the linear range was 0.08~40 μmol·L^-1, and the detection limit was 0.14 μmol·L^-1. The recoveries of hydrogen peroxide in tremella were 97.10%~107.08%, and the relative standard deviation (RSD) was less than 5%. In this study, a simple, rapid, low-cost and sensitive visual detection of hydrogen peroxide was achieved without special detection equipment, which is conducive to the rapid promotion of quantitative detection of hydrogen peroxide in the food field and clinical practice.