Synthesis of gold nanoparticles of morphology other than spheres or rods in a single step by combining the radiolytic and chemical methods has been investigated. These eds of gold nanoparticle are generated in situ by irradiating aqueous solution containing 4x10^-4 mol dm^-3 gold precursorion (AuIII), 0.1moldm^-3 cetyltrimethyl ammonium bromide (CTAB), 0.2mol dm^-3 isopropanol, 6x10^-5 mol dm^-3 Ag⁺ and 7.2x10^-4 mol dm^-3 ascorbic acid (AA) at a dose rate 3.4kGyhr^-1. After a short irradiation time sufficient number of seeds were formed in the solution. AuI present in the system get adsorbed upon these seeds and then subsequently reduction of AuI to Au0 by scorbic acid and growth of these eds results information of gold nanoparticles. TEM image confirmed that plate like gold nanoparticles have been formed. The anisotropic growth of nanoparticles was found to be controlled by bilayer structure of CTAB and selective adsorption of silver ion present in the system.