The invention relates to an engine plateau environment laboratory which comprises an intake pressure simulation system, an exhaust pressure simulation system, a high and low temperature control chamber and a control system. The high and low temperature control chamber is used for placing an engine, the intake pressure simulation system is formed by sequentially connecting an intake pressurizer tank, a low-temperature box body and a refrigeration unit, and the exhaust pressure simulation system comprises an exhaust heat exchanger, an exhaust pressurizer tank, an exhaust electric control valve, a vacuum pump and a gas-water separator. Dispersive high-altitude natural environmental conditions (pressure, temperature and moisture) are intensively simulated in the laboratory, thereby improving the precision and the efficiency of the engine high-altitude environmental experiments.