Due to environment concern, the current lubricant such mineral oil-based lubricant is not environmentally friendly as it were not readily biodegradable and toxic. Therefore, the vegetable oil-based lubricant has been promoted in order to replace mineral oil-based. In this study, the performance of lubricant for six different ratios between RBD Palm Olein and Semi-Synthetic oil were tested in different loads and been discussed in different parameters including coefficient of friction, wear scar diameter, surface roughness, flash temperature parameter and wear worn surface. Four-ball tribotester machine used to evaluate performance of sample lubricants using ASTM D4172 standard. From the results, it shows that the sample lubricants for engine oil mixing with RBD Palm Olein reduce in 38% of coefficient of friction compared to pure engine oil. From overall of the results, the performance of lubricant was improved as RBD Palm Olein mixing with engine oil.