Crack opening displacement and the numbers of screw dislocations distributed at the interfacial crack tips of a piezoelectric body were investigated. By using RiemannSchwarz’s symmetry principle and the singularity analysis method of complex functions, the general solutions of the problem were presented. Numeric curves show that piezoelectricity has less effect on the interfacial crack opening displacement, while the numbers of screws dislocation and biomaterial properties have obvious effect on the interfacial crack opening displacement and the numbers of screw dislocations.