In the field of the industry control the controlled system is usually coupling. And the experiment of process control in the simulation environment has a big gap with the actual operation.So this paper presents a kind of decoupling control of the multivariable control system based on YC-SX multivariable control experiment platform.In the process of the research,the model of multivariable quadruple tank system is built by using this experiment platform.And the system identification and decoupling control of the system are realized by using Matlab software.At last,the result of the study shows that the coupling of the quadruple tank is basically eliminated, and the design can be more close to the actual situation of the project.