Instruction simulation device and method thereof

An instruction simulation device and a method thereof are provided. The simulation device includes a monitor, which is configured to determine whether a ready-for-execution instruction is an instruction under a new/extended instruction set sharing the same instruction set architecture as that of the processor. If the ready-for-execution instruction is an extended instruction, it is converted into a simulation program which consists of a compatible instruction sequence further composed of at least one native instruction of the processor or a compatible instruction recognizable/executable by the processor. An execution result of the extended instruction is simulated by executing the simulation program, thereby extending the service life of an electronic appliance embodied with the disclosed simulation device therein.