Abstract: The issues of easy implementation to select the contraction-expansion factor for variable universe fuzzy controller and the real-time control are discussed,and a new selection method is provided.Comparing with the integral and exponential type selections,the new contraction-expansion factor selection method takes the advantages of containing fewer parameters and consuming smaller computing resource.Then the parameter selecting rules are given by simulation,and applied practically to the exothermic batch reactor to set the fuzzy reasoning of the variable universe fuzzy controller.It is observed that the new contraction-expansion factor is effective to ensure not only high control precision,but also fast tracking ability,which gives a support to apply the variable universe fuzzy controller to practical control engineering.