13 shots of shock compression data were measured for enstatite (Mg0.92, Fe0.08)SiO3with initial density of 3.06g/cm3up to 140 GPa, using impedance‐match method and electrical probe technique. The relationship between shock wave velocityDand particle velocityucan been described linearly by:D= 3.76 +1.48u(km/s), and no evidence of phase transition was shown in the experimental shock pressure range. Our experimental Hugoniot is about 7&percent; denser than the model Hugoniot of (Mg0.92, Fe0.08)O (Mw.) plus SiO2(St.) calculated by additive principle. This excluded the possibility that chemical decomposition of enstatite with perovskite structure to oxides would happen during shock compression up to 140GPa. The Gru¨neisen parameter &ggr;obtained by fitted our experimental data to: &ggr;=&ggr;0(&rgr;0/&rgr;)q, yields &ggr;0=1.84,q=1.69, with &rgr;0=4.19g/cm3. By using the third‐order Birch‐Murnaghan finite strain equation of state (EOS), Our shock experimental data yield a zero‐pressure bulk modulusK0s=260.09GPa and pressure derivativeK0s=4.17, given our new value of &ggr;, with &rgr;0=4.19g/cm3. From density constraint only, the purely perovskite model of (Mg1−x, Fex)SiO3(x=0∼0.1) can explain that of PREM well. © 2004 American Institute of Physics