Abstract: The Smoothed Particle Hydrodynamics (SPH) is a meshless and Lagrangian particle method which was successfully extended to computational fluid dynamics and elastic mechanics in the last decades. The computational tangle and torsion could be avoided in the calculation of structural deformation by using SPH. However, the numerical failure in the computation for two-order and more than two-order derivatives occurs in the study of elastic analysis. The present paper has developed an improved SPH which not only can avoid the computational failure, but also enhance computational precision. Despite the investigation is mainly focused on the structural small deformation, the conclusion is also suitable for the circumstance of the structural large deformation. Moreover, a numerical example is given and the error comparison of results is taken between the present method and ANSYS software.