The invention relates to a polyester filament, particularly to a low-melting-point polyester filament in skin-core structures. The low-melting-point polyester filament in the skin-core structures is mainly applied to fields such as nonwoven fabric such as carpets, decoration, glue-free cotton and hot pressing modeling and good in machinability, enables machining conditions to be easy to control and is low in energy consumption and good in spinning performance. The low-melting-point polyester filament in the skin-core structures is mainly formed by two layers of structures which comprise the skin layer and the core layer; the cross section of the low-melting-point polyester filament fiber is in round shapes and the like. The low-melting-point polyester filament in the skin-core structures solves the problems that preparation of the low-melting-point polyester fiber in the skin-core structures by composite spinning in the current is high in energy consumption and the condition stability is poor during the machining process.