The interaction of a piezoelectric screw dislocation in the matrix with interface effects under remote anti-plane shear stresses and in-plane electric loads in transversely isotropic piezoelectric solids was investigated. By using the complex variable method, the general solutions to the problem were given. With the aid of the Peach-Koehler formula, the explicit expressions of the image force acting on the screw dislocations were given. The results have indicated that the influence of the interface stress on the motion and the equilibrium of the dislocation near the inhomogeneity become significant when the radius of the inhomogeneity is reduced to nanometer scale. If the dislocation is located in the matrix, the positive interface effects can repel it. The soft inhomogeneity can also repel the screw dislocation near the inhomogeneity when the positive interface effect is considered.