The invention relates to an isothermal thermal forming hydraulic machine heating and heat preservation system and an operating method. The system comprises an upper heating platform, a lower heating platform and a heat preservation door. The upper heating platform and the lower heating platform each comprise a water cooling plate, heat insulation ceramics, multiple pressure bearing ceramics, an alloy steel heating platform, heating pipes and thermocouples. The alloy steel heating platforms of the upper heating platform and the lower heating platform are each provided with multiple independently-controlled heating regions. Each heating region is provided with an electric heating pipe, a temperature thermocouple and a temperature protection thermocouple which are independently controlled. The system has the advantages that the independently-controlled heating pipes in the alloy steel heating platforms of the upper heating platform and the lower heating platform are powered on for zone heating, the thermocouples are used for detecting the heating regions and adjusting the temperature differences between the heating regions at any time, it is guaranteed that the temperature difference of a whole work region of a hydraulic cylinder is smaller than a tolerance value, uniformity of temperatures in the upper heating platform and the lower heating platform is guaranteed, and the machining quality of workpieces is guaranteed. Energy is greatly saved, production cost is reduced, the machining period is shortened, and production efficiency is improved.