The air-liquid plate-fin heat exchanger for aircraft environmental control is provided with circulating cooling liquid on the hot side and stamping air on the cold side. Its heat transfer is closely related to the flight height and Mach number. In order to determine the working conditions of the heat exchanger to satisfy the heat transfer requirements, a method for calculating the rated heat transfer work envelope is proposed, then the parameters of the heat exchanger are calculated and optimized, and finally the work envelope and the structure of the heat exchanger are obtained. The vacuum chamber test is designed by selecting the typical working point on the working envelope, the heat exchanger performance is tested by simulating flight height and speed. The experimental results show that the heat transfer of the heat exchanger at each working point is 3.2% different from the rated heat exchange amount, and the results show that the calculation method of work envelope is feasible and accurate, which can provide reference for the optimal design of similar heat exchangers and the calculation of work envelope.