The cut steel strip is placed on the steel strip positioning fixture through the positioning hole, and 20 steel strips can be placed at one time (customized). The heat shrink pipe is automatically inserted into the steel belt on the fixture, and the position of the heat shrinkable pipe on the steel belt with the length positioning device on the fixture. Then the fixture of the steel belt is moved to the tunnel heat contraction furnace, and the track of the heat shrink furnace drives the steel belt clamp to shrink the heat shrink pipe to the steel belt through the high temperature heat shrinkage furnace.