Abstract: The single cylinder diesel engine is retained greatly and used widely. But it has problems of high fuel consumption and pollution. Combined with the construction features of single cylinder diesel engine, without constructional modification of the original engine, a set of fuel injection system was added. It can coordinate with the original fuel injection system. The way is to realize guiding fuel injection by means of mechanical control instead of high voltage electronic control injection system so that the mixture of diesel oil and air and the quality of the mixture gas are improved. The combustion process is improved so as to enhance the economy of fuel and reduce emissions of diesel engine. The experimental results show that the multiple fuel injection system achieves guiding fuel injection and is very useful for controlling emission, saving energy, reducing noise, by means of two injection pumps to supply oil for the same one injector separately, guiding fuel injection can be realized. It is very applicable and extendable for single cylinder diesel engine. Meanwhile, the theoretical bases for further study were provided.