Abstract: To meet the needs of manufacturers in the design and development of time service products, product finalization, factory inspection, and other processes on high-precision key indicators test inspection, a high-precision time server product performance verification test method is designed based on synchronization to UTC (NIM) time-frequency source, that is, the remote real-time traceability of NIMDO. By testing the time server using the crystal discipline algorithm with stepwise modulo operation compensation, when using different performance GNSS receiver modules A and B as external reference time sources, the average time deviation of the time server from NIMDO is 8.6 ns and 2.8 ns respectively using the designed test method, which meets the requirements of the key indicators of the product seriation in both standard type and high-end type.