The invention discloses a bidirectional tension line device, which belongs to a measuring device in the fields of water conservancy, transportation, rock and soil and the like. It includes a fixed end, a heavy end, a tension wire body, a two-way measuring point box, an automatic water adding device, a liquid storage tank and a connecting pipe. Two-way stretching line instrument; the connecting pipe connects the water box, liquid storage tank and automatic liquid adder in the measuring point box. The pulling line body is introduced from the fixed end, floats through each measuring point to the hanging heavy end, and Wrap the wire body around the idler wheel. The present invention changes the previous one-way tensioning line device and static leveling device which can only achieve a single measurement purpose, realizes dual-purpose one line, makes one bidirectional tensioning line device meet the requirements of the two sets of devices in the past, and saves a lot of cost.