Abstract: For researching and establishing a fast and convenient method to measure tannins in fruits and vegetables, the author chose the most widely applied method, Folin-Denis spectrophotometric method, as the basis to analyze the feasibility. The author adopted paired t-test, compared the results of experiments that used different tannins extraction solvents, temperature, duration time and coloring time upon the same sample, then did the verifying experiment against the method’ s linearity and accuracy. The experiment confirms that the best extraction and measuring conditions are: 500 W ultrasonic extraction, 20 minutes ultrasonic time, extraction solvent: H2O2, temperature 60℃ and coloring time 1 hour. The linear range of tannins measurement is 0- 30 mg/L; the detection limit is 0.2 mg/g; recovery rate is 95.8%- 101.9% ; RSD (relative standard deviation) is 1.07%- 4.29% . This method has the advantages of simplicity, quickness, high precision, good reproducibility, high recovery rate and low cost. It would be suitable for fast and accurate measurement of tannins in fruits and vegetables.