In order to get higher accurate phase of the double spacial frequency fringes, a method that employs the orders of projected fringes as axises to establish fringe-order-coordinate is presented. It makes the description of the fringe orders (phase) and their errors very direct and simple. In the fringe-order-coordinate, Bayes estimation method is used to amend the phase, and the more accurate phase is obtained. Emulational tests and actual experiments show that this method is effectual. With the application of this amending method in the actual experiment, the MSE of phase decrease from 0.014 rad to 0.009 rad, and the mean square error (MSE) of height decreases from 0.058 mm to 0.041 mm.