Abstract: 【Objective】 Under the background of global climate change, the obvious changes that had taken place in heat and precipitation resources in northern China were studied. Furthermore, the possible effects of climate warming on the agro-climatic resources and cropping systems in northern China were analyzed. 【Method】 Based on 308 meteorological observations stations from 14 provinces (municipalities and autonomous regions) in northern China, the inter-decadal and spatial variation trends of heat and precipitation resource were analyzed. According to the climatic regionalization indicators of cropping systems in China, the spatial displacement of planting north boundary during 1950s—1980 and 1981—2007 was analyzed. The major method used was choosing typical stations in the sensitive zone of cultivation northern boundary, and crop potential productivity step correction method to calculate the potential yield change due to cropping pattern shift between one crop (spring maize, spring wheat, winter wheat) a year and two crops (winter-summer maize) a year. 【Result】 Temperatures in northern China had generally increased, ≥0℃ accumulated temperature zone showed a north shift and a west spread, the cumulative effects of temperature rising were significant, the climatic tendency of cumulative temperature was 65.5 ℃•d/10a. Distribution of annual precipitation had presented a regional difference and reduced from southeast to northwest. Along to this, in the whole region it also showed a decreasing trend, the climatic tendency of precipitation varied from -90.0 mm/10a to 23.0 mm/10a, with an average level of -10.6 mm/10a. Under the combined effect of heat and precipitation, in the research area, the area of one-crop of cool-warm plants in semi-arid medium plateau in north (Ⅱ) declined, in area of one-crop of warm-cool plants in semi-arid low plateau in northeast and northwest (Ⅲ) increased in northeast China, and declined in North China and northwest China. The area of one-crop of warm-cool plants in semi-humid plain or hilly in northeast (Ⅳ) increased and the north boundary moved north in area of two-crops in irrigated land and two/one-crop in dry land in Huanghuaihai region (Ⅵ). Generally speaking, the northeast area boundary had a remarkable change, but was gradual and insignificant in southwest. In the sensitive areas which showed planting system’s north boundary changes, crop potential productivity increased significantly, from the area of one-crop of warm-cool plants in semi-humid plain or hilly areas in northeast (Ⅳ) to the area of two-crops a year, the yield increased by 1 979 kg•hm-2, which means that the annual production per unit area increased by 15.3%; from the area of one-crop of warm-cool plants in semi-arid low plateau in northeast and northwest (Ⅲ) to the area of two-crops a year, the yield increased by 7 912 kg•hm-2, which means that the annual production per unit area increased by 155.2%; in the area of one-crop of warm-cool plants in semi-arid low plateau in northeast and northwest (Ⅲ) where the spring wheat is changed to spring maize, the yield increased by 2 873 kg•hm-2, which means that the annual production per unit area increased by 51.7%. 【Conclusion】 In the context of global climate change, the≥0℃ accumulated temperature increased while the precipitation showed a decreasing trend in the research region. All of these caused a northwest movement of the north boundary line in sensitive zones of planting boundaries and the cropping system changes resulted in the increase of annual production per unit area.

Key words: climate change, northern China, cropping system, change of cropping boundary, production potential