The invention discloses a capacitor temperature rise measurement method and system based on heat flow measurement, and belongs to the technical field of electricity. The measurement method comprises the following steps of measuring the heat flow on a surface of a capacitor in the operation process by utilizing a heat flow sensor arranged on the surface of the capacitor; and calculating the surfacetemperature rise of the capacitor according to the thickness of the heat flow sensor, the heat conductivity coefficient of a heat resistor in the heat flow sensor and the measured heat flow, whereinthe arrangement position of the heat flow sensor on the surface of the capacitor is the surface of the capacitor and the position corresponding to the highest temperature point in the capacitor, or the position of the surface of the capacitor, which is closer to the low-voltage end; multiple heat flow sensors can be arranged, the surface temperature rise of the capacitor can be measured by each sensor, and the maximum value is used as the final measurement result. Compared with the existing capacitor temperature rise measurement method based on temperature measurement, the cost of capacitor temperature rise measurement in a high-voltage environment can be reduced.