During the past decades, biodiesel has attracted more and more attention as a renewable and environmental friendly fuel, owing to the high price of crude oil and growing environmental problems.Transesterification catalyzed by solid base catalysts was considered to be a more preferable production method because of their high catalytic activity and low cost.In this paper, K2CO3/Ca-Mg-Al hydrotalcite (HT) was prepared and pushed into catalyze the transesterification reaction of palm oil with methanol to obtain biodiesel.CCD method was used to determine the optima preparing cation ratio of the support Ca-Mg-Al HT.The calculation results showed that the catalyst with a support cation ratio around 1.5∶1.5∶ 1(Ca∶Mg∶Al) had the highest activity.With the best support, the mass ratio of K2CO3 was investigated, and the catalysts K2CO3/Ca-Mg-Al HT with the K2CO3 mass ratio above 50% all showed very high activity in the transesterification reaction.Taking economic factors into account, 50% K2CO3 was chosen as the best prepared mass ratio.Catalyzed by 50%K2CO3/Ca-Mg-Al HT, the transesterification reaction parameters as methanol/oil molar ratio, reaction temperature, catalyst amount, reaction time were investigated.Under the optima reaction as following: methanol/oil molar ratio of 12∶1,reaction temperature of 338K, catalyst amount of 5%wt./wt.oil, reaction time of 1h, the FAME yield could reached 99.2%.The XRD characterization results showed that K2CO3/Ca-Mg-Al HT maintained the layer structure of the support Ca-Mg-Al HT.As there were no characteristic peaks of K2CO3 but peaks belong to some new crystal phase in the XRD pattern of the catalyst, it was believed that K2CO3 had reacted with the support during the loading process.And combined with the reaction results, these new component was believed to be the active center of the catalyst.K2CO3/Ca-Mg-Al HT enlarged the family of HT supported solid base in the biodiesel production.Considering its lower price and non-toxic properties, it might be widely used in the continuous heterogeneous fixed bed techniques for biodiesel production.