The invention relates to a backfill soil construction method. A construction method for improving the compacting quality of a backfill soil with a high moisture content comprises the steps of dividing into multiple backfill compacting areas according to the actual site, and determining optimum moisture contents of various soil bodies on site through tests; determining actual moisture contents of the soil bodies in various areas on site through tests; formulating the mass ratio of the backfill soil in each area and a mixture by combining the data according to a self water absorption rate of the mixture; using an excavator for mixing on site according to the ratio, and accomplishing mixing quality control, drainage ditch setting, and measures for preventing from getting wet in the rain and ponding; after completing the mixture, mixing and using the mixture at the same time, and layered compacting; determining optimum compacting earthwork thickness, compacting times, compacting speed and other parameters of selected equipment through test sections; and accomplishing quality track, timely carrying out a soil test after layered compacting, and determining compacting factors. Compared with a traditional method, according to the construction method for improving the compacting quality of the backfill soil with the high moisture content provided by the invention, the construction period is shortened, the cost is reduced, and the problem of the compacting quality of the backfill soil with the high moisture content in moist and pluvial regions is effectively solved.