Abstract: It is essential for the underwear enterprise to make industrial patterns before cloth cutting and production.The quality of underwear product depends on whether the pattern is accurate or not.This thesis focuses on the rule of bra patterns′ grading.According to the pattern principle of bra,the grading rule of cup and ring,can find the general grading rule of the same-type bra.The general grading rule of the same-size bra can be found by researching on the human body size in different cup shapes and comparing the same-size bra with the same-type bra in the progressive change relations of pattern.