The present study considers the chemical reaction effect on mass transfer of an unsteady flow past a semi infinite vertical porous moving plate with time dependent suction and radiative heat source in presence of transverse magnetic field. The novelty of this study is to analyze the effect of chemical reaction on mass transfer of fluid flow in the porous plate. The analytical solutions for velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number are obtained by solving the governing equations of the flow field using multi parameters perturbation technique. The effects of the material parameters on the temperature, velocity and concentration profiles are discussed quantitatively.