Sulfated zirconia (SO4 (2-)/ZrO2) was proved as an efficient catalyst for the esterification of fatty acids and alcohols, the alkyl esters of long chain fatty acids are wildly used in industry and daily life. In this paper, the esterification of long chain fatty acid (both saturated and unsaturated) with simple alcohol catalyzed by SZ catalyst was presented. It is found that the degree of esterification reaction of the fatty acids with 1-butanol has a close relationship with the length and unsaturation degree of the chain. The longer the carbon chain is, the more difficult it is to react; the higher the unsaturation level is, the more difficult it is to respond. The related regulation will be confirmed and serve as the dictator for other reactions within this system.