The invention discloses a design method for an electric heater of a low pressure casting machine. According to the design method, the structure comprises a sealing cap, a sealing ring, a flange disc, a temperature detecting instrument, a hanger, an outer shell, an electric control cabinet, a moisture-proof base, a fixing support, a main power line, a point gauge, a fixing tube, a processor, an indicator gauge and an vice power line. The design method for the electric heater of the low pressure casting machine has the beneficial effects that the temperature detecting instrument is connected with the outer shell through the fixing tube and arranged in the outer shell through the point gauge to enable the outer shell to be capable of detecting the interior temperature of equipment, the interior temperature of the equipment is subjected to datum processing through the processor and displayed on the indicator gauge, the situation that work personnel monitor the interior temperature of the equipment in real time is facilitated, the error of the interior temperature and the control temperature can be found in time accordingly, and the machining quality is improved.