The utility model relates to an electric power operation technology field, more specifically relates to a drainage line coupling mechanism, and this drainage coupling mechanism includes staple bolt, drainage connecting portion, drainage fastener, drainage line, still includes to compress tightly the bolt, the drainage connecting portion for L shape, the drainage fastener be provided with the flexion, drainage connecting portion one end connect the staple bolt other end and be provided with triangle pole portion, drainage fastener one end hook be in in the triangle pole portion, compress tightly and tie turn the corner pars convoluta and flexion fixed connection, compress tightly and tie the head and set up to the plane, the terminal surface tieing head and triangle pole portion that compresses tightly compress tightly, triangle pole portion two other terminal surfaces with the drainage fastener compresses tightly, the drainage fastener other end connect the drainage line. Thereby effectively improve the area of contact of drainage fastener and drainage connecting portion to effectively reduce the probability of drainage connecting portion fusing.