This study investigated which conjugated linoleic acid (CLA) and leucine (LEU) ratio optimized the improvement of pork quality when added to finishing pig diets. A total of 120 finishing pigs were randomly assigned to five treatments, including a control diet and a 2 (LEU 1.0 and 2.0%) by 2 (CLA 0.5 and 1.0%) factorial design. The animals had free access to the diets and water. The pigs were slaughtered at 125 kg body weight. Growth performance, carcass characteristics, meat quality, sensory evaluation and serum cholesterol levels were measured. Data for each measured factor were analysed using the GLM procedure in SAS (1996). Analytical results revealed the IMF percentage (1.24, 1.04, 1.66, 2.31 and 1.61% for TRT1 to TRT5, respectively) and tenderness (2.14, 2.27, 2.32, 2.57 and 2.44 for TRT1 to TRT5, respectively) of the loin eye muscle were significantly (P<0.05) improved by the CLA 0.5% combined with LEU 2.0%. Other indicators (such as growth performance, meat quality, carcass measurements and serum cholesterol level) were not affected by the LEU and CLA supplementation.