The invention discloses a vacuum gas diaphragm circulating pump for tritium purification. The circulating pump is a micro pump body which has a dual-cavity and double-layer structure, and comprises a bracket, a base, a primary container, a secondary container and a motor. The primary container is fixedly arranged on the bracket; the base is connected with the primary container; the secondary container is arranged on the base; and a first diaphragm cavity structure and a second diaphragm cavity structure which are arranged inside the primary container are bilaterally symmetrical. The motor is arranged in the secondary container. The vacuum gas diaphragm circulating pump can greatly reduce the working pressure of a circulating pump so as to meet the requirement of tritium purification and separation treatment on a lab scale, also can shorten the tritium recovery time, improves the tritium recovery efficiency, reduces the risks of tritium leakage and hydrogen storage bed toxification, and enhances the safety of the tritium treatment process.