The invention discloses a bottom sealed type open caisson wall and a construction method. The bottom sealed type open caisson wall comprises a caisson wall body, blade legs, a bottom water-stop sheet, water inlets and water outlets. The water inlets and the water outlets are provided with open and close valves. High-pressure water flow is jet through the water inlets to cut a soil body below the bottom water-stop sheet of the caisson wall body, the high-pressure water flow and the soil body are mixed into muddy water, and the muddy water is pumped to the ground surface through the water outlets; under the action of gravity and the external force, the caisson wall body of an open caisson gradually sink till the caisson wall body sinks to the designed depth; then, reinforcing pulp is injected from the water inlets and the water outlets, and high-pressure slip casting blocking is carried out on the soil body below the bottom water-stop sheet till the anti-permeability meets requirement; and then the bottom water-stop sheet is demounted and an open caisson wall bottom plate is constructed. According to the bottom sealed type open caisson wall and the construction method, water outside the caisson wall body can be prevented from permeating into the caisson wall body, the conventional underwater excavating manner is simplified through the water injection and water pumping processes, the bottom plate quality is good, the construction environment is good, safety is high, the schedule is high, and the underground excavation construction safety of a water-rich stratum can be ensured.