A hydrophobic, low-loading and alkylated polystyrene-supported sulfonic acid (LL–ALPS–SO3H) has been developed for several organic reactions such as the hydrolysis of thioesters, the deprotection of acetals and an acetonide, and the hydration of an epoxide and an alkyne in pure water on the basis of remarkable effects of both the polymer structures and loading levels of the sulfonic acid catalysts.