The invention discloses a worry-free start-up system of an electrical-controlled common-rail engine. The worry-free start-up system comprises an oil tank, an oil delivery pump and a fine filter, wherein an exhaust device for discharging oil gas is arranged between the oil delivery pump and the fine filter; and an outlet of the exhaust device communicates with the oil tank through an oil pipe. According to the worry-free start-up system disclosed by the invention, the exhaust device is arranged at an oil inlet of the fine filter, so that air in the fine filter is exhausted from the exhaust device, active air exhaust can be realized, and the start-up property of the engine can be effectively improved.