The use of Natural Gas (NG) in internal combustion engines has been increased in this decade. The objective of this paper is to investigate the NG injection timing on the dual-fuel engine. In this paper experimental based on dual fuel engine strategy (DFE strategy) was tested with several variations of gas injection based on CA at the modified direct - injection engine into a DFE strategy. In the data test, the variation is CA 260, 244, 230, 214 bTDC. This research is for observed how it affects the engine performance. The indication of the effect of NG injection based on the CA variation is the non-homogenization of the NG-air mixture in the intake manifold, and the delay in mixing NG-air to go into the combustion chamber. From several data tests that have been done, there is an increase in engine power, thermal efficiency and a decrease in SFOC fuel consumption. The optimum combination of the DFE strategy has a fluctuating value when taken from test experimental data. The trend is seen, that CA 230 bTDC is the optimum value to be operated in the DFE strategy. Because there is an increase in Torque, Efficiency thermal, and a decrease in SFOC of fuel consumption.