(Purpose) Although the existence of regional disparities among local governments is inevitable, it needs to be reduced in order to improve the efficiency of resource allocation and create equity in the policy environment. As a starting point for narrowing the regional disparity in Korea and in China, this paper attempts to find out the variations and fundamental causes of the regional disparity from 1985 to 2019 in terms of GRDP. (Design/methodology/approach) For this, the characteristics of regional disparities are investigated by computing the Gini coefficients for the GRDP and per capita GRDP of local governments in both countries, and the Gini coefficient decomposition method is used to explain the major causes of regional imbalances. (Findings) The results derived from analyzing the major factors of economic disparity with the Gini coefficient, the contribution of the economic disparity between and within metropolitan areas is similar to the factors of the overall economic disparity in Korea. On the other hand, it can be seen in China that local government factors at the regional level are greater since the contribution of the disparity between regions is greater than within a region. (Research implications or Originality) Therefore, for Korea both policy efforts of local...