The invention discloses a flexible frost-heaving-resistant anti-scouring channel protective structure and a construction method, and relates to the technical field of channel engineering. The flexiblefrost-heaving-resistant anti-scouring channel protective structure is formed through construction operations such as repair leveling, grooving, composite geotextile bag paving, operation of scouringmud into a composite geotextile bag, sewing and fixing. The flexible frost-heaving-resistant anti-scouring channel protective structure is high in construction efficiency, is convenient in material taking, has characteristics such as excellent deformation adaptation coordination ability, good freezing resistance, a smooth surface and strong erosion resistibility as a flexible composite geotextilematerial design is adopted; and compared with a conventional rigid protective structure, the flexible frost-heaving-resistant anti-scouring channel protective structure is more suitable for channel protection in an alpine region, can effectively prolong the safe service life of the channel protective structure, guarantees integrity of the channel, improves water conveying efficiency of the channel, and effectively guarantees ecological environments at the two sides of the channel.