Abstract: The basic characteristics of satisfactory optimization are put forward which are different from the traditional optimization,and a new satisfactory optimization model of parameter design of control system is proposed.Through the utility function and its expectation function,the satisfactory algorithm based on utility function is put forward,and the characters of boundary closed convexity and the basic operation characters under nonnegative measurable value function are discussed,which offers the basic theory for the application of the proposed algorithm.A simulation example of single loop control system is given to prove that the satisfactory optimization algorithm under the utility function has a favorable astringency.