A unit area standard investment estimation method(UASIEM) and a key project investment estimation method(KPIEM) are established to estimate amount of investments Jiangsu needs in regional land exploitation projects, key land exploitation projects and key engineering projects. Factors affecting investment in land exploitation and reorganization are analyzed, and their weights are worked out by grey incidence analysis, thus the parameter n of KPIEM are calculated. Based on the above-described SIPAEM and KPIEM methods, the total amount of investments in land exploitation and reorganization and the amount of investments in key projects in Jiangsu Province, PRC during the period from 2001 to 2010 are calculated respectively.