Disclosed is a nylon thread drying device. The nylon thread drying device comprises a box body. A first fixing plate is fixedly connected to the bottom of one side of the box body, a first connecting rod is fixedly connected to the top of the first fixing plate, a first fixing block is fixedly connected to the side, close to the box body, of the first connecting rod, and a first pulley is fixedly installed at the end, far away from the first connecting rod, of the first fixing block. Due to the fact that heating devices are arranged, nylon thread wound on the surfaces of second pulleys can be heated, primary heating treatment can be conducted on the nylon thread, and the nylon thread can make direct contact with a heat source so as to be effectively dried through drying treatment. Due to the fact that a drying box is arranged, the internal temperature of the drying box can rise through a heating pipe and a first heating wire arranged inside the drying box, hot air is blown by a second fan into the box body along through holes, and the enough high temperature of the box body can be guaranteed to conduct drying on the nylon thread. The drying effect of the nylon thread can be doubly enhanced through two-step drying, and the quality of the nylon thread can be improved.