The utility model provides a portable DC power supply return circuit capacitance to ground tester, includes the DC power supply return circuit that ground clamp, earth connection, test wire, test host computer, current clamp, quilt were surveyed, current clamp signal input interface, signal amplification module, low -frequency signal generator, signal synchronization output module, signal source power amplifier, signal source output interface, signal synchronization processing module, rectifier module, signal filtering module, AD converter, working power supply module, CPU, signal input 0, display, casing, signal feed -in wire, this device simple structure, the integrated level is high, has characteristics such as small, light in weight, convenient to carry, and it is too big to know transformer substation's DC power supply capacitance to ground value to power operating person, and it has very strong practicality to move hidden danger by mistake to get rid of relay protection equipment, suitably each transformer substation's test.