Abstract: Experimental fan performance map is important for turbofan engine performance simulation,but the experimental data are always very limited.In order to get more information from the experimental data, the relationships between the increments of fan’s inlet and outlet total temperature and rotational speed under constant corrected spool speed were discussed.On the basis of the results,the relationship of the characteristic data was obtained and the constraint for fan performance map fitting was established.Via quadratic programming,a new method for fan performance map fitting was established.Numerical simulation was given which demonstrated the effectiveness of the method.