This paper presents a light-weight x86 emulator PIT (Portable x86 Instruction Translator) which is portable on multiple CPU architecture. “Dynamic binary translation” is a technique that can make instructions of one CPU architecture be capable of running on another CPU architecture. PIT utilizes portable dynamic binary translation technique to emulate Intel x86 instructions on multiple CPU architecture such as x86, PowerPC, ARM and Sparc. Users can load 16-bit or 32-bit user-level executable files of x86 system such as COM, EXE and ELF into PIT, execute them and observe the output. PIT utilizes Transferred Block Dynamic Cache and Condition Code Lazy Computation techniques to accelerate instruction translation. With virtual x86 MMU (Memory Management Unit), emulated instructions can address 4GB memory space in PIT virtual environment. With simple configuration and re-compiling, PIT can be easily ported and run x86 executable files on different CPU architectures.