Abstract: In order to discuss the nonlinear electromechanical properties of the La-modified lead zirconate titanate stannate antiferroelectric ceramics PbLa(Zr, Sn,Ti)O₃ (PLZST), the approximate linearized electrostrietive equations exactly the same form as the classical linear piezoelectric equations were derived from the second-order terms of the generalized piezoelectric equations. An analytic approach of solving the electroaeoustic transduction problems of the nonlinear antiferroelectric phase transitions ceramics transducers was presented. The nonlinear properties of the PLZST can be linearly equivalent with a maintained bias based on the approximate linearized electrostrictive equations for analyzing the electroacoustic transduction problems of the transducers. An innovative anti- ferroelectric ceramics low frequency class IV flextensional transducer with resonance frequency 1.1 kHz based on the approach was developed which utilizes the PLZST as active elements. The lake authentications indicated that the use of PLZST for transducers yielded presently a 3 dB increase in TVR and a 9 dB increase in SL over its PZT-4 counterpart, and the approach was valid.