The issue of economic development disparities has become one of the hot topics in the academic study. This paper intends to discuss the issue by taking Huaihai Economic Zone as a research object, which is a typical provincial border-region. First, this paper introduces the development of Huaihai Economic Zone and the extent of academic domain. Then it makes a critical review on research into economic development disparities. Supported by softwares of SPSS and ArcGis, the authors select 126 counties of Huaihai Economic Zone as research units, and use the data from statistical yearbooks of Huaihai Economic Zone cities covering the years of 1995, 2000 and 2005. Based on studies on evolution of economic development disparities, this paper draws some onclusions as follows. From 1995 to 2005, the counties of Huaihai Economic Zone can be divided into four types: the most developed counties, more developed counties, moderately developed counties and hysteretic counties. Huaihai Economic Zone is a less developed region and its intra-regional economic gap has been widened in the 10-year period. North Jiangsu and South Shandong are more developed than East Henan and North Anhui, and South Shandong has developed more quickly than North Jiangsu since 2000. North Anhui was behindhand from 1995 to 2005 in the zone. Some 30% of the counties of Huaihai Economic Zone made steady contribution to the regional development. On this basis, according to economic development level, this paper studies region division. Results show that this zone can also be divided into four areas: the most developed central area, more developed southern area, more developed northern area, hysteretic western area. Finally, the paper puts forward some suggestions on breaking down administrative barriers, starting Huaihai Economic Zone Planning, and establishing National Overall Planning Regional Trial Zone of Comprehensive Coordinated Reform, so as to achieve comprehensive and harmonious development in the Huaihai Economic Zone.