The invention belongs to the technical field of fuel system, and particularly discloses a daily oil tank oil supply system. The oil supply system comprises a fuel tank, an oil storage tank and a transfer pump. The lower part of the oil tank is connected with an oil inlet pipe. The oil inlet pipe is connected with the transfer pump. The upper part of the oil tank is connected with an oil outlet pipe. A filter screen is arranged in the oil tank in a sliding mode in the vertical direction. The filter screen is used for filtering impurities in the fuel oil. The oil tank top cover is slidably connected with a sliding rod. The lower end of the slide bar penetrates through the filter screen and extends to the lower part of the filter screen. The sliding rod is in sliding fit with the filter screen. The end of the oil outlet pipe is fixed on the sliding rod and located above the filter screen. The lower end of the sliding rod is fixedly connected with a slag suction disc. A cavity is arrangedin the sliding rod. A slag suction cavity is arranged in the slag suction disc. A slag suction opening is arranged in the side wall of the slag suction disc. A sealing ring used for sealing the slag suction opening is arranged on the slag suction disc in a sleeved mode. A push rod is connected to the sealing ring. The push rod is arranged on the slide rod in a sliding mode. An annular air bag is arranged in the slide rod in a sleeved mode. According to the scheme, impurities can be effectively and quickly treated, so that the fuel oil pumped out of the oil outlet pipe is free of impurities.