Abstract: This paper presents a performance assessment method for a kind of linear time-varying multiinput-multioutput(LTV MIMO) control systems of which the time delays can be decided.A matrix factor named interactor matrix,equivalent to process delay in univariate loops,is defined.Using the interactor matrix and normal multiplication,a set of systematic algorithm and process to set up feedforword plus feedback minimum variance(MV) benchmarking is proposed for LTV MIMO control loops.In order to acquire MV benchmarking,the computing characteristics of LTV systems should be taken into consideration,and the actual MV output instead of the interactor filter MV output should be used.Theoretical research and simulation show that the presented method can assess LTV MIMO process accurately and effectively.