A gas forklift is often fueled by LPG or gasoline that emit toxic exhaust emissions, smoke, fumes and odors. These emissions become quite serious when forklifts are operated in confined areas. It is bad for the forklift operators as well as other workers who are inhaling the fumes. With cleaner burning natural gas, forklift operators and fellow workers are exposed to considerably less emissions. This study aims to develop the fuel system for the CNG-converted forklifts which is composed of hardwares and control algorithm for LPG forklift engine. The engine torque, power and emission in LPG fuel mode are measured to evaluate the difference of CNG engine performance. Based on the results, it is transparent that CNG-converted forklift is an very effective way to reduce the amount of CO, NMHC and NOX in the exhaust gas, which proves the developed control system is effective for CNG forklift engine.