In order to dynamically analyze the change of water resources carrying capacity and accurately identify the vulnerable indexes, the idea of universal gravitation and damping coefficient is used for reference to construct gravity based subtractive set pair potential, which can reflect the relation and situation of set pair events. The method of gravity based subtractive set pair potential was applied to the dynamic analysis of the water resources carrying capacity evaluation, and compared with the existing subtractive set pair potential. The results show that the dynamic analysis of the water resources carrying capacity of Anhui province by the gravity based subtractive set pair potential and the comparison of the situation analysis of subtractive set pair potential are consistent, and the correlation coefficient between the two kinds of set pair situation is close to 1.0; according to the gravity based subtractive set pair potential, the indexes of vegetation coverage rate, population density, sewage discharge reaching the standard, water quality reaching the standard and ecological water use rate in the water functional area in 2005-2015 are the vulnerability indexes of water resources carrying capacity evaluation in Anhui province, which should be mainly controlled. And other indicators need to be improved. Therefore, the gravity based subtractive set pair potential is feasible for the dynamic evaluation and diagnosis of water resources carrying capacity in Anhui province; and gravity based subtractive set pair potential has strong potential interpretation, simple calculation, practical results and strong applicability. The method provides a new way for judging the current condition and development trend of the set pair events, and has application prospect in system dynamic analysis and evaluation.