A three-dimensional non-isothermal viscoelastic droplet impacting onto solid wall was numerically simulated using the smoothed particle hydrodynamics (SPH) method, in which the elastic stress of the fluid was characterized by the Phan-Thien-Tanner (PTT) constitutive model. To suppress tensile instability, an artificial stress term was introduced. GPU parallel computing was employed to improve the computational efficiency of the 3D simulations. The accuracy and validity of the proposed SPH method were verified through simulations of two benchmark cases: a two-dimensional non-isothermal Poiseuille flow and a three-dimensional isothermal droplet impact on a solid wall, with results compared against those from other numerical methods. Based on this validation, the 3D non-isothermal droplet impact process was further investigated. The convergence and parallel performance of the method were assessed, and the effects of initial droplet temperature, temperature-dependent parameters, and other physical properties on the spreading dynamics were analyzed. The numerical results demonstrate that the proposed SPH approach can accurately and efficiently simulate complex 3D non-isothermal viscoelastic droplet impact phenomena, offering valuable insights for related applications.