Considering the characteristics of the surrounding rock structure and the stress field for gob-side entry retaining, the unbalanced bearing characteristics of gob-side entry retaining is presented, and the main roof structure is simplified as a mechanical model composed of roadside support body and the roadside coal body. The unbalanced bearing coefficient is proposed, which is defined as the ratio of solid coal body bearing and roadside support body bearing, and then an expression is derived for calculating the unbalanced bearing coefficient. The main factors influencing the change law of the unbalanced bearing coefficient are analyzed. The results show that the unbalanced bearing coefficient is positively correlated with solid coal elastic modulus and the immediate roof damage variable, and negatively correlated with the roadside support body elastic modulus, the immediate roof elastic modulus, the roadway width and the roadside support body width. Based on the change law of the unbalanced bearing coefficient for gob-side entry retaining, the control countermeasures are determined against surrounding rocks around gob-side entry retaining of 4211 air-return gate in Liujiazhuang Colliery. The unbalanced bearing characteristics of gob-side entry retaining with high-water materials as roadside backfill is demonstrated by the methods of FLAC3D numerical simulation and the field monitoring. The research results have been applied to the gob-side entry retaining of large mining height successfully.