Besides the existing regime of legal entity, recently in China more nove1 forms of legal entity have been emerging and developing. With being prevai1ing in commercial practice, cooperation agreements satisfy the parties' special requirement that the intensity of the cooperative relationship should be set between that in general contracts of sale of goods and in partnership agreements. According to parties' various goals and demands in contractual relationship, cooperation agreements applied in practice principally fall in three categories as follows, contractor-cooperation agreement, coalition-cooperation agreement, lease-cooperation agreement. By the categorization of cooperation agreements, essential elements thereof could be explored and some coherent rules cul1ed from the cacophony of judicial decisions. In conclusion, both the commercial and judicial practice of cooperation agreements has been so wel1-developed as to be codified in our contract code.