Abstract: The reciprocating system supported by gas springs are widely used in engineering,such as free-piston Stir-ling engine,compressors,etc.Focusing on dynamic behavior of the reciprocating system with asymmetric gas springs in Linear Alternator(LA)-driven mode,a nonlinear dynamic model considering stable and intermittent gas flows in pipe-lines and sealing gaps is established,the dynamic characteristics are obtained through numerical calculation.Furthermore,equivalent stiffness characteristics of asymmetric gas springs of the reciprocating system are obtained and analyzed based on time-frequency domain transformation.The nonlinear dynamic model is proved to be valid based on comparison with experimental measurements.The modelling and analysis results can provide theoretical basis and guidance for the design of the reciprocating system applied to reciprocating machinery.