A low‐temperature reaction is of considerable importance in avoiding the degradation of phytosterol esters caused by high temperatures. In this study, an efficient method under mild conditions was developed to synthesise phytosterol esters by using microwave‐assisted catalyst dodecyl benzene sulphonic acid (DBSA). The phytosterol conversion reached 94.27% under the optimal conditions: oleic acid to phytosterol molar ratio of 2.5:1, catalyst dosage of 20% (mol%) and reaction temperature of 60°C for 60 min. Fourier transform infrared (FTIR) spectroscopy was applied to determine the structure of phytosterol oleates. Moreover, a second‐order kinetic model describing phytosterols esterification exhibited an adequate agreement with the experimental data. Microwave irradiation achieved the reduction of energy barrier (Ea = 29.17 kJ mol−1) in comparison with conventional heating (Ea = 49.22 kJ mol−1). This study suggests that microwave‐assisted catalyst DBSA is a reliable and efficient method for the production of high‐quality phytosterol esters.