Diclofenac acid is a non-steroidal anti-inflammatory drug which is a commonly used drug in our daily life.It is one of drugs used on clinical in great number for its wide uses and indication.NSAID is the third largest category of drugs besides antibiotics and vitamins,They share nearly the same pharmacological mechanisms,inhibiting synthesis of cyclooxygenase(COX).As COX catalyzes the conversion of arachidonic acid to PG,the inhibition of COX means the inhibition of PG synthesis.PG(particularly PGG2 and PGE2) is the major media of inflammatory substances and pain in body.Therefore,NSAIDs have anti-inflammatory and analgesic effects.