The invention discloses a mechanical seal assembly identification system of a reactor main pump. The mechanical seal assembly identification system comprises a water tank, a meter pump valve pipeline system and a static pressure testing apparatus, wherein the static pressure testing apparatus comprises a simulation support tube and a simulation pump spindle inserted in the simulation support tube; the lower end periphery of the simulation pump spindle is in seal connection with that of the simulation support tube; an annular cavity is formed between the simulation pump spindle and the simulation support tube and is used for accommodating a first shaft seal assembly and a second shaft seal assembly of the main pump; the water tank guides water flow during the process for simulating the actual operation of the reactor into the static pressure testing apparatus, the first shaft seal assembly and the second shaft seal assembly through the meter pump valve pipeline system. The mechanical seal assembly identification system can simulate the environmental condition of the first shaft seal assembly and the second shaft seal assembly during the actual operational process of the reactor through three pipelines and truly reflects the leakage rates of the first shaft seal assembly and the second shaft seal assembly so as to reflect that whether the first shaft seal assembly and the second shaft seal assembly can meet the operational technical specification requirements through the measured value of the leakage rates.