In this research, we have synthesized polystyrene sulfonic acid as a new heterogeneous solid acid. Then, we have synthesized 2,3-dihydroquinazolin-4(1H)-ones via condensation of 2-aminobenzamide and different aldehydes in the presence of polystyrene sulfonic acid. The major advantages of the present method are good yields, ecofriendly and easy work-up.