The engine cooling fan is an important part of the vehicle cooling system． Static pressure and shaft po- wer are important indicators to evaluate its aerodynamic performance，and the tip of the blade as a main part of the fan work has a great influence on the aerodynamic performance of the fan． Taking the cooling fan of the engine as the research object，the calculation method of aerodynamic performance of the fan and the optimization method of blade tip parameters were studied． Firstly，the calculation method of fan aerodynamic performance was given，and the fan calculation model was established according to the test bench． Then a new fan was designed with the tip mounting angle，the tip length and the tip arch height as the variables． Based on the orthogonal test method，the parameters of the blade tip parameters were optimized and combined，and the optimization method of the fan tip pa- rameters was given． Finally，the optimization results were further analyzed from fan performance curve，blade pressure diagram and blade velocity vector diagram，and the feasibility of the optimization method was verified． This analysis and optimization method of fan tip parameters is of guiding significance for the design of engine cooling fan．