The invention discloses an unpowered water purification system for a riverfront landscape constructed wetland, comprising a riparian wetland constructed along a lake-land ecotone of a river, lake-pond. The riparian wetland comprises a plurality of alternatively arranged wetland islands and watercourses formed between them. The bottom surface of the riparian wetland is lower than the normal water level of the river, lake-pond, and the upper surface of the wetlands is flush with the normal water level of the river, lake-pond. Plants are planted on the wetlands. A revetment is constructed between the riparian wetland and the river, lake-pond, and its upper surface is between the bottom surface of the riparian wetland and the upper surface of the wetlands. The invention achieves good purification and landscape effects. The purification system has some advantages such as good landscape effects, simple management without energy and power consumption, and thus is durable and stable.