Abstract: The paper comes up with a more practical optimization design method. An enhanced target function is built up via Lagrange multiplier and the principle of equal mini rate of consumption increasement and the method of static boiler model analysis are put forward. Also, new requirements on the property of consumption function are introduced. The theory of load assignment is described through some examples. Special problems coming up in these examples are dealt with, reaching actual value results. For various groups of boilers, once the definite characters of fuel consumption function are given, the load assignment optimization scheme among boilers running in parellel can be obtained by this kind of linear planning method.