Abstract: Through the investigation on the grassland ＇no-rodent damage model district＇ from 2008 to 2010, the rodent population density, birds of prey and food kernel number, herbage yield and biomass were analyzed to explore the effect of biological control of pest. The results showed that： the number of effective rodent caves in all plots decreased from 2008 to 2010, and birds of prey and food kernel number per kilometer increased year by year; the grassland biomass in three years was increased by 27.7%, the vegetation coverage was increased by 43.8%, and the pasture height was increased by 22.9%; the establishment of scaffolding to control mice saved 43 697.4 tons of fresh forage loss total, and recalled the economic loss of 7 739 480 yuan; grassland biomass increasing value during the year was 8 739 480 yuan; the establishment of scaffolding used natural food chain and food structure factor net in grassland ecosystem to control rodents from the angle of ecology, could protect the ecological environment of grassland, improve grassland deratization effect so as to get the target of effectively controlling the rodent quantity for long tenn.