The invention relates to an electronic control unit of an engine. The unit comprises a master control chip, a signal conditioning circuit connected with the master control chip, a drive chip connectedwith the master control chip, and a drive circuit connected with the drive chip. The drive circuit comprises an oil injector drive circuit and an ignition drive circuit. The signal conditioning circuit is used for obtaining running information of the engine. The master control chip is used for determining the oil injection time and the ignition angle according to the running information and controlling the drive chip to drive an oil injector of the engine to conduct oil injection at the oil injection time through the oil injector drive circuit and to drive an ignition coil of the engine to conduct ignition according to the ignition angle through the ignition drive circuit. By means of the electronic control unit, oil injection and ignition can be accurately controlled, accordingly, the engine can be in the best combustion state, and therefore the pollutant dismounting amount can be greatly reduced, and the fuel oil combustion cost is reduced.