The invention discloses a method for testing water holding capacity of gel. In the testing method, a detection principle of differential scanning calorimetry is initiatively utilized. The method comprises the steps that a gel sample is placed in a testing area of a thermal analyzer, and a reference sample is placed; a protective gas is continuously introduced into the thermal analyzer, the temperature of the thermal analyzer is increased to 20-500 DEG C, and heat preservation is performed at the temperature; and a DTA value, changed along with the temperature, of the gel sample is recorded, aheat enthalpy value delta H of water molecules in the gel sample is obtained by calculation, and finally the water holding capacity of the gel is accurately reflected by the heat enthalpy value deltaH. According to the testing method, the testing time of a single sample is 15-20 minutes; the detection speed is high; the repeatability of a detection result is relatively good; and the detection accuracy is high.