Abstract: Disclosed is a device of automatically detecting nucleic acid, including: a fixing frame; a cartridge positioning assembly having a cartridge loading position configured to position a cartridge; a lifting assembly including a lifting base configured to be controllably moved toward or away from the cartridge positioning assembly in a first direction; a rotating assembly including a rotating member capable of controllably rotating relative to the lifting base around a rotation axis parallel to the first direction; and a liquid transferring assembly including a connecting portion configured to connect to a tip. The liquid transferring assembly is capable of rotating with the rotating member to a position where the connecting portion is aligned with any liquid storing tank of the cartridge in the first direction, the liquid transferring assembly is capable of moving along with the lifting base to an inserting position or a disengaging position along the first direction.