The data of herbage growth and its affecting meteorological factors at Enkhbayar Animal Husbandry Meteorological Experiment Station in Tongliao were used to analyze the climatic factors affecting the herbage growth in the northern Horqin grassland. Results indicated that the average temperature in the study area in recent 27 years increased by 0.16 °C·(10a) ~(- 1), the average precipitation decreased by 23.96 mm·(10a) ~(- 1), the dryness index in herbage growing season increased by 0.15 (10a) - 1,and the drought in the grassland became more serious. Moreover, the period of seedling establishment of Leymus chinensis,Agropyron cristatum and Potentilla chinensis was delayed, the flowering stage of which was in advanced,and the growth season of which was shortened. Precipitation was the main factor affecting the period of seedling establishment and withering stage of the three plant species, it was negatively correlated with the period of seedling establishment but positively correlated with the withering stage of the three plant species. The herbage height and yield were significantly decreased (P < 0.01),and the decreases were 0.88 cm and 121.43 kg·hm ~(- 2) per year respectively. The herbage height and yield were mainly negatively correlated with temperature,but positively correlated with precipitation. Under climate warming,water has become more and more important for the herbage growth in the study area. The analysis with the integral regression model showed that the positive effects of precipitation and sunshine duration in mid-May on the herbage yield were the highest from the period of seedling establishment to the leaf expansion stage. The jointing stage and flowering stage from late-May to mid-June were the main stages for the herbage growth of demanding precipitation and sunshine,and the period from late-June to mid-July was the main stage for herbage growth of demanding heat. The effect of air temperature on herbage yield was negative in August,especially in mid-August.