A wire-grasping structure for a terminal block is disclosed. The wire-grasping structure includes a core, a conductive terminal piece and a screw. The core is transversely formed with a socket and vertically formed with a threaded hole. The socket and the threaded hole are communicated mutually and each communicated with the exterior of the core. The conductive terminal piece has a receiving portion and a terminal portion. The terminal portion is configured to be horizontally inserted into the socket such that the receiving portion projects from the core terminal portion. The screw is configured to be vertically screwed in to the threaded hole and enter the socket to abut against the terminal portion. Thereby, the wire-grasping structure can store a jumper bar and facilitate convenient use.