Based on the modified conjugate gradient method that is used in finding the same constraint solution of the matrix equation
a modified conjugate method was proposed to find the different constraints solution of multivariable matrix equation.With this method
the different constraints solution can be obtained within finite iterative steps in the absence of round off errors.The different constraints solution with least-norm can be got if some special initial matrix is chosen.In addition
the optimal approximation matrix of a given matrix can be obtained in the set of the different constraints solution.