These facts motivated us to do comparative studies to identify the underlying contributors to the inconsistency in optimization. In this study, refined canola, unrefined canola, and unrefined camelina with similar carbon chain length, were chosen as representative feedstocks to examine the impact of unsaturation degree and feedstock properties on biodiesel optimization. RSM was used in all cases to keep the optimization method consistent, levels of four independent factors (temperature, reaction time, catalyst loading and molar ratio of methanol/oil) were set in the same range, and the responses included product yield, FAME yield, and biodiesel yield. This study aims to provide answers to these questions and invite more research efforts on this topic.