Production of alternative fuels that are economical, environment friendly, energy efficient has become a necessity because of rise in prices of petroleum and diesel. Catalytic cracking of Jatropha curcasa oil can yield hydrocarbons of liquid fuel range. In the present study, catalytic cracking of Jatropha curcasa over ZSM-5 catalyst in a fixed bed reactor at atmospheric pressure has been carried out. The effect of temperature, tetralin-oil ratio and catalyst on the yield of organic liquid product (OLP) and yield of hydrocarbons range has been studied. The products were analysed by Gas chromatography flame ionization detector (GC-FID). Design expert software has been used for designing the experiments to observe the effect of parameters over conversion of Jatropha curcasa oil to hydrocarbons of liquid fuel range. A set of 17 experiments with constant feed flow rate and tetralin-oil ratio in the range 0-0.2 were carried out. The operating temperature was kept between 400-450°C and the amount of catalyst has been varied from 1-2 gm. The OLP yield decreased with increase in temperature and amount of catalyst. The optimum condition for obtaining C6-C8 range hydrocarbons was at temperature 425°C with 2g catalyst and without tetralin. The optimum conditions for obtaining C9-C13 range hydrocarbons was at temperature 425°C with 1.5 g catalyst and 10% tetralin. The optimum conditions for obtaining C14-C18 range hydrocarbons was at 450°C with 1 g catalyst and 10% tetralin.