The invention relates to the technical field of belt weighers, in particular to a high-precision quantitative feeding belt weigher which comprises a base, four weighing sensors are installed on the top of the base, a weighing belt is installed on the tops of the four weighing sensors, a scraper is installed on the top of the base, the scraper and the weighing belt are installed in a matched mode, and the scraper and the weighing belt are installed in a matched mode. A U-shaped mounting rod is mounted on the side portion of the base, a feeding frame is mounted at the top end of the U-shaped mounting rod, and two through holes are formed in the side portion of the feeding frame. During feeding, materials can be put in through the feeding frame, and when the materials do not reach the standard, the output end of a telescopic hydraulic cylinder stretches out to drive a telescopic shaft and a baffle to move downwards, so that the materials are fed into the feeding frame; and meanwhile, the anti-blocking mechanism can be driven to rotate, so that the materials are prevented from being accumulated in the feeding frame, and two material guide trapezoidal plates are pushed to be away from each other, so that a discharge port is enlarged, and the materials can quickly reach the specified weight.