Abstract: For a semiactive or active control system,although there are many classic algorithms available,their applicability and control efficiency are not ideal due to systematic features of nonlinear behavior,time variable and parameter uncertainties.On the contrary,since fuzzy control systems are mathematical models free,these difficulties can be overcome.Therefore,many researchers have adopted fuzzy logic approach for structural control.This is very useful for structural vibration control.However,fuzzy control theory still lacks a systemic design guidance to set up the corresponding rule-bases at present,and accordingly the rule-bases need often be revised repeatedly.In order to solve this problem,a new idea for structural control,i.e.the off-and-towards-equilibrium(OTE)control strategy,is presented and developed in this paper.For a fuzzy control system,a set of rules can be extracted easily on the basis of the idea.In this paper,numerical simulations are carried out to study the seismic response control of a multi-storey structure with an active tendon system(ATS)installed in the first storey,and the rule-bases of the corresponding fuzzy control system according to the OTE control strategy are established.Simulating results verify its rationality and validity by comparing the earthquake responses of the structure using the OTE strategy during the earthquakes to those using the LQR algorithm.