The invention provides a multifunctional converter for a relative dielectric loss tester, belonging to the field of electrical equipment. The multifunctional converter comprises at least one analog signal input port, wherein an operational amplifier U1 is arranged at the output end of the analog signal input port, and an analog-digital converter U2 is connected with the output end of the operational amplifier U1, the output end of the analog-digital converter U2 is connected with the input end of an operation processor, and the output end of the operation processor is connected with a field effect tube U4; a relay used for circuit switching is arranged on the circuit of the analog signal input port, and a control chip is arranged on the control loop of the relay. According to the multifunctional converter, analog/digital-amplification-digital/analog conversion is carried out on an analog signal acquired by a sampling unit, and a standard analog signal output is provided to the back-end multifunctional converter, relative dielectric loss testers of different manufacturers are adaptive and universal to sampling units of different manufacturers, the equipment universality can be improved, purchasing of a great amount of fitting equipment can be avoided, and the purchasing cost can be reduced.