The quasi-static and dynamic mechanical properties experiment of Al6061-T6 in high temperature (20~500℃) and high strain rate (up to 104/s) was carried out on the quasi-static press and split Hopkinson press bar (SHPB) equipment. Then the effect curves of strain hardening, strain rate strengthening and thermal softening were obtained. According to these curves, the classic JC (Johnson-Cook) equation was modified. Furthermore, the modified JC equation was validated in the high speed cutting physical simulation model. The results showed that the Al6061-T6 flow stress increased with the increasing of strain and strain rate, and obviously decreased with the increasing of deformation temperature. The description accuracy of the modified JC equation was higher than the JC equation. The obtained Al6061-T6 constitutive equation can provide important material parameters for physical simulation models of its high speed machining process.