Tin (IV) phosphate (SnP), as a mesoporous material, was prepared through a simple one-pot synthesis method and the produced mixture was transferred into autoclave. Then, it has been modified by loading the appropriate amount of sulfamic acid (SA) using the impregnation technique. Pure and modified SnP have been characterized by using X-ray analysis (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. Acidity measurements were examined using potentiometric titration and pyridine adsorption. The total number of acid sites and Brønsted to Lewis acid sites ratio (B/L) recorded high surface acidity after loading sulfamic acid. The catalytic activity of the solid catalysts was confirmed in the synthesis of 3, 4-dihydropyrimidinone. The highest catalytic performance was displayed in the reaction in case of 25 wt% SA/SnP. Also, the adsorption behavior of Pb (II) was studied for SnP and SA/SnP. The results reported an efficient adsorbent of SA/SnP for metal.