The invention relates to the fields of photovoltaic industry and water purification and particularly relates to a photovoltaic driving, heat preserving pressurizing and ultrafiltration integrated water purifying device. A photovoltaic system comprises a solar cell panel, a DC/DC circuit, a DC/AC inverter circuit and a storage battery, wherein the DC/DC circuit is connected with two output ends of the solar cell panel, the DC/AC inverter circuit is connected with the output end of the DC/DC circuit, and the input end of the storage battery is connected with the output end of the DC/DC circuit. A heat preserving pressurizing system comprises a three-phase asynchronous motor, an alternating submersible pump, an electric heating element and a pressure pump, wherein the three-phase asynchronous motor is connected with the output end of the DC/AC inverter circuit, the alternating submersible pump is connected with the output end of the three-phase asynchronous motor, the electric heating element is connected with the output end of the DC/AC inverter circuit, and the pressure pump is arranged in a water storage device. The integrated water purifying device is low in operation cost, is a water quality preparation system for safe drinking water, is significant for the improvement of the water quality of drinking water, the prevention of diseases, the improvement of health level of people and the guarantee of social stability and has very good economic, social and ecological benefits.