Linear alkylbenzene sulfonate (LAS) is an important industrial anionic surfactant. It is usually made by sulfonation of linear alkylbenzene (LAB) in a falling film reactor with sulfur trioxide gas. In this paper, LAS was prepared in a rotating packed bed (RPB) with dilute liquid sulfur trioxide, followed by aging treatment inside the RPB. The influences of the rotating speed, the sulfonating agent concentration, the SO3/LAB molar ratio, the sulfonation temperature in the sulfonation step and the aging residence time as well as the different reactor design on the aging step onto the sulfonation process were all examined. In the sulfonation step, the LAS concentration reached 91.75% at a lower temperature owing to the intensified micro-mixing performance of the RPB. In the aging step, the RPB can significantly shorten the aging time. The RPB shows great potential for the industrial application of sulfonation.