This paper establishes a functionally graded material (FGM) piezoelectric nanobeam model that considers surface effects, higher-order electric fields, and Winkler-Pasternak elastic foundation constraints, investigating the influence of various parameters on its force-electric behavior. Based on Hamilton’s variational principle and the Euler-Bernoulli beam model, the governing equations and boundary conditions of the FGM piezoelectric nanobeam are derived. By employing the Fourier series expansion method, analytical solutions for deflection, polarization intensity, and electric potential are obtained. The effects of gradient index, residual stress, surface material parameters, and Winkler-Pasternak parameters on the deflection, polarization intensity, electric potential, and bending stiffness of the FGM piezoelectric nanobeam are analyzed in detail. The study reveals that an increase in the gradient index and residual stress leads to greater deflection, while an increase in the Winkler-Pasternak parameters reduces deflection. As the gradient index increases, the bending stiffness decreases. Furthermore, polarization intensity increases with external load and applied voltage but decreases with increasing gradient index and thickness.