Mathematical model of cross type multi-stream plate-fin heat exchanger was established. Meanwhile mean square error of accumulative heat load was normalized by dimensionless

and the equations of temperature-difference uniformity factor were improved. Evaluation factors above and performance of heat exchanger were compared and analyzed by taking aircraft three-stream condenser as an example. The results demonstrate that the mean square error of accumulative heat load is common result of total heat load and excess heat load between passages. So it can be influenced by passage arrangement

flow inlet parameters as well as flow patterns. Dimensionless parameter of mean square error of accumulative heat load can reflect the influence of passage arrangement to heat exchange performance and will not change dramatically with the variation of flow inlet parameters and flow patterns. Temperature-difference uniformity factor is influenced by passage arrangement and flow patterns. It remains basically unchanged under a certain range of flow inlet parameters.