The invention relates to a low-temperature urea crystal simulation test system for an SCR catalytic silencer. The system comprises a hot air system, a urea jetting system, a nozzle cooling system and a to-be-tested SCR catalytic silencer, wherein the hot air system comprises a hot air device, a hot air pipeline and a throttle valve; the urea jetting system comprises a urea pot and a jetting pump; and the nozzle cooling system comprises a cooling pump, a pump water inlet pipe, a pump water outlet pipe, a nozzle cooling water inlet pipe, a water pool and a nozzle cooling water outlet pipe. According to the invention, the hot air system is used for simulating the exhaust of a diesel engine, the urea jetting system is used for simulating the urea jetting volume of the urea when the SCR catalytic silencer works, and the nozzle cooling system is used for controlling the temperature of the urea entering the SCR catalytic silencer, so that the purpose of simulating the low-temperature working condition of an engine pedestal is achieved, and the simulated low-temperature working condition of the engine pedestal is utilized to realize the urea crystal test for the SCR catalytic silencer in a low-temperature state.