A double fleece knit fabric constructed on a circular knitting machine and comprising three kinds of yarns, i.e., inlay (A1,A4), tie-in (A2,A5) and knit-in (A3,A6), in which tie-in yarns are all knitted and knit-in yarns are either knitted or welted. Preferably, a series of an inlay yarn, a tie-in yarn and a knit-in yarn constitutes a block, and in a first block, a portion of the inlay yarn is tucked and held down by a tie-in loop, which is overlapped and intertwined by a knit-in loop, and in the block adjacent to the first block, a knit-in yarn is welted in the same wale in which the inlay yarn of the first block is tucked.