The invention provides a compact type liquid-helium-free 1K low-temperature refrigeration device suitable for ultrahigh vacuum environment. The device comprises a gas conveying pipe, a pre-cooling end, a protection cover, a pressure reduction pool and an air exhaust device. The device has the beneficial effects that firstly, the protection cover reduces the surface area of a refrigeration machine exposed in a vacuum cavity and can be used for the ultrahigh vacuum environment; secondly, the protection cover serves as a backflow channel of refrigeration working media, conductance of the backflow channel is improved, it is ensured that liquid refrigeration working media in the pressure reduction pool have the low vapour pressure, and the lower refrigeration temperature is achieved; thirdly, at the initial cooling stage, the backflow channel can be inflated with helium exchange gas so as to rapidly cool the portion of the pressure reduction pool, and the cooling time is shortened; fourthly, due to design of the second segment of the protection cover, the whole heat exchange efficiency is improved; fifthly, the refrigeration device has the beneficial effects of being compact in structure, easy to demount, mount and maintain, adjustable in refrigeration amount and the like.