Abstract: The active methodology of time correlation coincidence measurement of neutron is an effective verification means to authenticate uranium metal. A collimated ²⁵²Cf neutron source was used to investigate mass and enrichment of uranium metal through the neutron transport simulation for different enrichments and different masses of uranium metal, then time correlation coincidence counts of them were obtained. By analyzing the characteristic of time correlation coincidence counts, the monotone relationships were founded between FWTH of time correlation coincidence and multiplication factor, between the total coincidence counts in FWTH for time correlation coincidence and mass of ²³⁵U multiplied by multiplication factor, and between the ratio of neutron source penetration and mass of uranium metal. Thus the methodology to authenticate mass and enrichment of uranium metal was established with time correlation coincidence by active neutron investigation.