To meet the stringent overlay requirements, it is desirable to select appropriate elements to compensate and adjust the magnification of the projection lithographic lens with double telecentricity. A simple and practical method to tolerance the magnification is presented. This method uses the commercial optical design software and the finite difference algorithm to calculate the magnification sensitivity for some tolerances, and then selects the optimal magnification compensator with the consideration of the wave aberration sensitivity. By using this method, the magnification tolerance is analysed and the magnification compensator is selected for a projection lens with the working wavelength of 193 nm and numerical operture of 0.75. The results show that the lens achieves 50×10-6 magnification adjustment, and the root-mean-square degradation of lens wavefront aberration is less than 1.5 nm.