Abstract: To solve the problem that it is difficult to estimate the interactor matrix,minimum variance(MV) benchmarking bound is proposed to assess multivariable systems' performances.Another new MV benchmarking lower bound is established, it can be acquired from the process data and diagonal interactor matrix.Combined with these bound establishing methods,a new integrated MV benchmarking bounds performance assessment theory system of multivariable control system is constituted.Simulation results show the above assessment methods are effective.