The article was mainly discussed the design method of the sabot which is adopted the unequal pith in design for APDS structure. The guiding idea was different forced part adopted different pitch, and it was carried on the approximate equivalent stress design and calculation for the danger section of the sabot. Compare with the sabot which is adopted the equal pitch and the same danger section; it can decrease the stress on the danger section effectively, reduce the negative weight, and increase the muzzle kinetic energy. The design thinking of this article has instructive effect to some extent for design the structure of APDS.