The invention relates to a pressure vessel type water decontamination device. The pressure vessel type water decontamination device is characterized by comprising a cylindrical shell, and end caps are arranged at two ends of the shell respectively and provided with a water inlet and a water outlet respectively. A middle supporting plate is arranged in the shell and partitions the interior of the shell into an upper space and a lower space. Front and rear sides of the middle supporting plate are connected with the inner side wall of the shell respectively, and the left side and the right side of the middle supporting plate correspond to joints of the shell and the end caps at two ends respectively. An upper seal plate is arranged between the right side of the middle supporting plate and the upper end of the right side of the shell, and a lower seal plate is arranged between the left side of the middle supporting plate and the lower end of the left side of the shell. One or more filter tanks are transversely arranged on the middle supporting plate and extend into an upper space of the shell through the middle supporting plate, and the lower end of each filter tank is provided with an opening. The pressure vessel type water decontamination device has advantages that safety and a water filter function can be guaranteed, and filter efficiency is improved.