An approach was proposed to reduce grinding errors and improve meshing performance. Firstly, both a controllable contact path and a high order transmission error（H-TE） curves were designed based on the TCA theory, and the parameters of curves were got by optimizing the minimum amplitude of LTE based on LTCA, and topologically modified tooth of pinion was determined according to movement of the rack generating involute tooth. Secondly, a free-form CNC grinding machine model of five-axis was established and kinematic relationships of the axes were derived. Besides,an error correction model based on a sensitivity analysis of the grinding wheel and the movement of five-axis was determined, and grinding error was established by estimating whether the wheel contact with the pinion, and the corrections were solved by using the PSO optimization algorithm. Finally, an example shows that the optimized higher-order transmission error curves is smooth at the intersect points, and topologically modified tooth is characteristics of more modification and proximal diagonal at engaging-in and engaging-out regions. Besides, a middle concave higher-order transmission error curve makes a smaller LTE amplitude, which helps to reduce vibration；Further more, the parameters of concave depends on working condition, and with the increasing of loads, the optimal parameters value increases. The modified tooth can be efficiently ground by slightly adjusting five-axis movement and the wheel profile according to the solved corrections and then by flat grinding wheel for diagonal correction, which effectively reduce the grinding errors to 2 μm.