Optimization study on NiO-CaO5/SiO2-Al2O3 catalysed deoxygenation of triolein towards paraffin yield was investigated. Response surface methodology-central composite design (RSM-CCD) was used to design the experiments with three operating parameters: catalyst loading (1-9 wt.%), reaction temperature (270-390 degrees C) and reaction time (30-150 min). The present study indicated that maximum yield of straight chain hydrocarbons (73.3%) was achieved under deoxygenation condition of 7 wt.% of catalyst, 340 degrees C within 60 min, which the interaction effect between reaction temperature-catalyst amount greatly influenced the straight chain hydrocarbons yield. In addition, the generated RSM model was statistically significant and adequate to predict the results with minimum error of <4%. The NiO-CaO5/SiO2-Al2O3 catalysed deoxygenation of triolein was mainly occured in decarboxylation/decarbonylation (deCOx) pathways of decomposed oleic acid, which lead to the majority of straight chain hydrocarbons at carbon ranged of C-17. Furthermore, the NiO-CaO5/SiO2-Al2O3 catalyst showed high reusability with maintained the straight chain hydrocarbons yield (>65%) for 4 consecutive reaction cycles. (C) 2016 Elsevier Ltd. All rights reserved.