The invention discloses an indoor air quality improvement method and a multifunctional indoor plant landscape device. According to the method, a first-stage water-washing treatment function area, a second-stage underwater purifying and filtering treatment function area, a third-stage soil purifying treatment function area and a fourth-stage plant stem and leaf purifying treatment function area areset up; and after indoor air is pumped into the first-stage water-washing treatment function area by an air pump, the air is purified through the first to fourth treatment function areas, and microenvironment comfort degree factor improvement is realized through the soil-water-plant ecological system. According to the method and the device, the natural beauty and the functional practicability arecombined in a cooperative manner, ornamental plants having various beautiful forms and purifying functions are combined organically, the spatial levels are rich, pollutants such as particulate matters, formaldehyde and the like in the indoor air can be purified, the effect of improving the air quality can be realized, meanwhile, the environment can be beautified, the atmosphere of returning to the nature can be built, and the graceful, cozy, green and ecological home or office environment can be created.