Using the model of grating pair compressor with negative dispersion, the formulae of dispersion errors for the femtosecond chirped-pulse amplification system are presented. The relationship of the adjusting accuracy in the stretcher/compressor versus the distance, incidence angle, and density of the grating pair is discussed theoretically. The demand of adjusting accuracy for different width of input pulse is also studied. The grating incidence angle and the grating density must be selected properly to satisfy the requirement of the system and at the same time decrease the adjusting accuracy. The highest precision is offered to the grating incident angle in the system. The higher alignment sensitivity is needed for the shorter pulse duration. The mutual compensating among varied order dispersion should be considered to optimize whole system, allowing the decrease of the adjusting accuracy.