From the angle of mutual joining network in the capital market , we discuss the problemof financial asset portfolio optimization and balance scale. Under the conditions of non2balance of financial assets and liabilities , we give the control models of investment scale and risks for the single department . From financial network and analyze the balance problem of financial instrument between the many department and establish the models describing the balance scale and price of system. Under the function of different investment effectiveness , the best optimization so2 lution is found to the single and many department models