Blade is a special type of parts, and its type face demands extreme high accuracy, therefore, its error must be strictly controlled in the machining process. The causes and effective estimation method of nonlinearity error were analyzed. Combining with linear interpolation principle, a non-linear motion error estimation model and error compensation model were established. Using Java language, the dedicated postprocessor for blade five-axis machining with a non-linear error compensation function was developed based on the VMC850F machine movement solving. The correctness and practicality of the postprocessor are verified through an impeller cutting experiments.