The invention relates to an oil control system of a diesel/natural gas dual-fuel internal combustion engine. The oil control system of the diesel/natural gas dual-fuel internal combustion engine can effectively solve the problem that control accuracy and refit effects are poor. According to the structure of the oil control system of the diesel/natural gas dual-fuel internal combustion engine, a microcontroller is connected with a programmable logic controller, a sensor is respectively connected with the input end of the microcontroller and the input end of the programmable logic controller, the output end of the microcontroller is connected with a switching circuit, the output end of the programmable logic controller is connected to an actuator, the switching circuit is respectively connected with diesel ECU driving signals, artificial loads and an oil atomizer, the oil atomizer is connected with the actuator and a sampling instrument, the sampling instrument is connected with a comparator, the comparator is connected to the programmable logic controller, and the artificial loads are connected with the sensor through a detector for detecting fuel injection pulse width. The oil control system of the diesel/natural gas dual-fuel internal combustion engine is simple, novel and unique in structure, and accurate and reliable in control, is effectively applied to dual-fuel diesel high pressure common rails, electronic controlled monoblock pumps and pump nozzle engines, can completely avoid influences of pilot injection, post injection and other multiple times oil injection signals of an original vehicle under a duel-fuel mode, reduces oil consumption of the system, and improves the substitution rate.