In this paper, an analytical investigation of nanofluid flow and heat transfer in a rotating system is studied by a semi exact method based on weighted residual called least square method. We used this method to solve the governing nonlinear coupled equations of the described problem and compared it with numerical method (Runge-Kutta 4th order). Comparisons indicate that least square method is so suitable computational process. The results indicate that skin friction parameter increases with augment of Reynolds number and rotation parameter but it decreases with increase of injection parameter. Also it can be found that Nusselt number has a direct relationship with Reynolds number and injection parameter while it has a reverse relationship with rotation parameter, Schmidt number, thermophoretic, and brownian parameter.