Given a connected graph , the revised edge-revised Szeged index is defined as , where , and are the number of edges of lying closer to vertex than to vertex , the number of edges of lying closer to vertex than to vertex and the number of edges of at the same distance to and , respectively. In this paper, by transformation and calculation, the lower bound of revised edge-Szeged index of unicyclic graphs with given diameter is obtained, and the extremal graph is depicted.