The invention discloses a floating and sinking type water purifying system. The floating and sinking type water purifying system comprises a tank body, wherein a treatment area and a clean water area are arranged in the tank body; at least one part of the tank body is arranged in a water body of the water source; the part, corresponding to the treatment area, of the tank body is provided with a water inlet for a water source to enter the treatment area. The floating and sinking type water purifying system has the advantages that the traditional water intake type and water intake source are changed; the water body of the water source automatically flows into the tank body to purify, so that the arrangement of the water intake power source is not needed, and the power consumption due to long-time running of the water intake power source is decreased; the whole treatment device is arranged in the water body, the occupation of land source is not needed, a large amount of land source is saved, the running cost is reduced, and more energy-saving and environment-protection effects are realized.