The embodiment of the invention discloses a liquid separator which comprises a liquid separator barrel, wherein the liquid separator barrel is provided with a telescopic section capable of stretching out and drawing back to change the volume. According to the liquid separator, the liquid separator barrel is additionally provided with the telescopic section capable of stretching out and drawing back to change the volume. The volume of the liquid separator can be changed to be applicable to different compressors by changing length of the telescopic section, so that reduction of the development cost is facilitated, the working efficiency is improved, and the development cycle is shortened for productization as soon as possible. The invention further discloses a compressor.