The invention discloses a high-voltage test transformer insulation heat treatment system and a heat treatment method thereof. At present, there are many testing and evaluating means for transformer insulation and ageing at home and abroad, and no very good post insulation heat treatment means exits. The system comprises a transformer heat treatment tank, a vacuum degree sensor, a capacitance transmitter, a temperature transmitter, a vacuum pump, a heating device and a control device connected with the vacuum degree sensor, the capacitance transmitter, the temperature transmitter and the heating device; capacitance information collected by the capacitance transmitter comprises capacitance between winding layers of a transformer and between winding and a grounding transformer heat treatmenttank in the heat treatment process, and the control device controls the heating device and the vacuum pump to work according to the collected capacitance information so as to quantitatively control the heat treatment process. According to the technical scheme, qualitative effect analysis and quantitative calculation analysis of insulation treatment can be achieved conveniently, the controllable insulation treatment process is achieved, and the uncertainty of transformer insulation treatment for a high-voltage test is eradicated.