This paper presents a novel and effective cell-based smoothed alpha radial point interpolation method (CS-αRPIM) using αPIM shape functions for approximating displacement and cell-based smoothed strains for displacement gradient construction. Using a scaling factor α [0, 1], the αPIM shape functions are combinations of the condensed RPIM (RPIM-Cd) shape functions and the linear PIM shape functions, where the former often leads to a "softer" CS-RPIM model, and the latter a "stiffer" linear CS-RPIM model (which is as same as linear FEM), compared to the exact one. Through adjusting the value of α in our new CS-αRPIM, the stiffness of the model can be "designed" for desired purposes, such as for seeking nearly exact solutions in strain energy norm (or possibly other norms). A simple and practical procedure to search for such an α has also been presented. Some 2D and 3D numerical examples are studied to examine various properties of the present method in terms of accuracy, convergence and computational efficiency. © 2013 World Scientific Publishing Company.