Abstract: Production-living -ecological space refer to the general name of space divided according to the main functions of land use, which are the basic paradigm of macro-scale understanding of land. It is of great significance to promote the healthy and sustainable development of land space in grain main production area and to ensure national food security for accurate identification of production space, living space and ecological space in grain main production area. Therefore, Keshan County, a typical grain main production area in the northern Songnen Plain, China, was taken as the research area in this study. Based on the vector data of the land use change survey in 2015 and the land type map spot area in Keshan County, the analysis of basic area units in this study were calculated and a fine-grained geographical grid was established. Referring to the existing research results, the types of production, living and ecological land were divided in turn from the perspectives of industrial attributes, social attributes and management attributes of land use, and an evaluation index system of production, living and ecological land in the research area was constructed according to the strong and weak differences of land use versatility, which combines classification and functional differences. Using the method of coupling coordination degree and Inverse Distance Weight (IDW) interpolation, the coordination among production, living and ecological functions in each analysis unit was quantitatively calculated. Based on the coordination degree of functions, the production, living and ecological space in the research area were accurately identified under fine-grained grid, revealing the spatial pattern of the research area. The results showed that: 1) The production function value in the study area was relatively high and the distribution was relatively balanced without obvious spatial differentiation characteristics, but there were small areas with low production function value in the northern, central and central southern parts of the study area; The high-value areas of living function are mainly distributed in rural residential areas and towns in dots or lumps. At the same time, the living function and production function had obvious spatial consistency after removing the high-value areas. Ecological function, production function and living function showed significant spatial complementarity, and the spatial pattern of the three-living in the study area conformed to the basic characteristics of the main grain producing areas. 2) According to the level of coordinated development of the three-living function, the research area could be divided into three-living dysfunction area, running-in area and coordination area, and the proportion from large to small was three-living function running-in area, coordination area and imbalance area in turn; The running-in area was distributed throughout the study area, the coordination area was mainly concentrated in the central and eastern parts of the study area, and the imbalance area was distributed in the northern and central and southern parts of the study area in the form of lumps and strips. The coupling and coordination of the three-living functions in the study area was relatively good. 3) The research area could be identified and divided into six types of spaces, namely: production space, living space, ecological space, production-living space, production-ecological space, production-living-ecological space; Production-ecological spatial distributed throughout the study area, Production-living-ecological space mainly distributed in the central, eastern and western parts of the research area, while other functional areas scattered sporadically in the research area. The research area, as a whole, presented a land spatial pattern with production-living-ecological space and production-ecological space as the main body and accompanied sporadically by other functions. The research results can provide scientific basis for the delineation of "three areas and three lines" in major grain producing areas.