The invention provides a high-latitude high-temperature permafrost area highway raft plate-pile composite foundation and a construction method. In the prior art, the hydration heat generated by CFG piles during construction would have a large effect on permafrost around the piles and therefore the lateral restraint would be obviously reduced after the permafrost melts, so that the bearing abilityof the CFG piles would be obviously affected. The high-latitude high-temperature permafrost area highway raft plate-pile composite foundation comprises a foundation; the foundation comprises a group of prefabrication piles (8); inter-pile soil (7) is arranged between each two adjacent prefabrication piles; the lower portions of the prefabrication piles pass through humus (3), peat soil (4) and a high-temperature permafrost layer (5) sequentially and are located on a pile foundation force holding layer (6); the tops of the prefabrication piles extend into a raft plate (1); an XPS thermal insulation plate (2) is arranged under the raft plate and a cotton-padded mattress cushion layer (12) is arranged under the XPS thermal insulation plate. The invention is applied to the high-latitude high-temperature permafrost area highway raft plate-pile composite foundation and the construction method.