Reciprocityisthebuildingblockofhumancooperativerelationship. Thisisthereasonwhy internationaltradeagreementsregarditastheirfundamentalprinciple. Inthemultilateraltradingsystem， though not definitely defined，reciprocity，together with the most-favored-nation principle，is one of its pillars. Reciprocityisthemotivationandstrategyforbilateralnegotiation，whilemost-favored-nationisa mechanismtomakethatbargainingresultmultilateral. Correspondingtotheconditionalandunconditional MFN，there are two kinds of reciprocity: specific and general. As the general reciprocity does not strictly emphasizeequivalent concessionandinterestbalance，themultilateral tradingsystemis a mixtureof spe-cificandgeneral reciprocityandhas developedintoathree-tierstructureforthetreatmentamongdeveloped， developingandnon-market-economy members.