Abstract: To overcome mass data, long duration, instability and uncertainty in the test of triangle orientation discrimination (TOD), a simulation method for IR scanning imaging systems is presented. A simulation platform for predicting IR imaging systems performance was established,and the triangle pattern images were discriminated by human eyes. According to the results, training was carried out for the neural network. Based on the predictive method of TOD by the neural network, the direction of the simulation spline is discriminated, the correct discrimination probability was obtained by utilizing the statistical method, and the TOD prediction curve is achieved. Experimental results show that the predicted TOD curve is consistent with the measurement.