This paper is concerned with the control performance assessment based on the multivariable generalized minimum variance benchmark An explicit expression for the feedback controller-invariant (the generalized minimum variance) term of the multivariable control system is obtained, which is used as a standard benchmark for the assessment of the control performance for multi input multi output (MIMO) process. The proposed approach is based on the multivariable minimum variance benchmark In comparison with the minimum variance benchmark, the developed method is more reasonable and practical for the control performance assessment of multivariable systems. The approach is illustrated by a simulation example and an industrial application