The utility model discloses a low-pressure oil passage real-time monitoring system, an electronic control system and a vehicle electronic-controlled engine. The low-pressure oil passage real-time monitoring system comprises a pressure sensor, a vehicle controller and an alarm apparatus, wherein the pressure sensor detects the oil passage pressure value of the fuel oil inlet of a fine filter, the vehicle controller compares the oil passage pressure value with a preset pressure value in the vehicle controller. The pressure sensor is mounted on the fine filter, and the output end of the pressure sensor is connected with the input end of the vehicle controller. The vehicle controller controls the alarm apparatus to give out alarm according to the comparison result of the oil passage pressure value and the preset pressure value. The electronic control system comprises the low-pressure oil passage real-time monitoring system, and the vehicle electronic-controlled engine comprises the electronic control system. The low-pressure oil passage real-time monitoring system is simple in structure and high in efficiency, monitoring intermediate links are few, modification over the oil passages of the electronic-controlled engine is small, modification and upgrading of vehicles can be carried out conveniently, design is exquisite, overall cost is lower, and the low-pressure oil passage real-time monitoring system, the electronic control system and the vehicle electronic-controlled engine can be applied and popularized in the field of vehicle electronic-controlled engines in a large scale.