A visualization study of natural gas direct injection combustion was carried out by using a high speed video camera. The results show that the distribution of the stratified mixture differs with the injection mode, with parallel and single injection tending to form a higher degree of mixture stratification than opposed injection. Flame propagates toward the downstream direction in the cases of parallel and single-injection combustion, and flame propagates outward from the centre of the combustion chamber in the case of opposed injection combustion. A characteristic of turbulent combustion with a wrinkled flame front is presented in natural gas direct injection combustion. Superlean combustion can be realized owing to the formation of an ignitable stratified mixture with the optimum setting of the fuel injection timing.