In order to study the influences of the rotational restraint at pile head and the slight initial inclination of pile shaft on lateral pile responses under simultaneous vertical and lateral loads, semi-analytical solutions were put forward by matrix calculation, based on the coefficient of subgrade reaction expressed in the three-parameter form. The results were validated by the comparison with model test results and the existing solutions. The results indicated that when the coefficient of rotational restraint at pile head increases, the displacement at pile head and the maximum bending moment under ground decrease, while the bending moment at pile head and the distance between the maximum bending moment under ground and pile head increased. Both the maximum displacement and bending moment increased linearly with the increase of the initial inclination angle of pile shaft, and their changing rates increased when the vertical load increased. When the vertical load increased, the maximum displacement and bending moment increased, and their changing rates increased with increases of the vertical load and the initial inclination angle of pile shaft. The distance between the maximum bending moment under ground and ground decreased linearly when the vertical load increases.