The invention relates to a glue injection method of a fuse. A positioning slot for accommodating a composite insulator fitting is arranged in the middle of a composite insulator vertically. The method comprises: a composite insulator and a composite insulator fitting are fixed by clamps; glue injection is carried out to solidify the composite insulator fitting; and the clamps are loosened to complete glue injection. Because the composite insulator fitting and the fuse are fixed respectively by the clamps, a problem that when a worker holds the composite insulator fitting, the worker can not wait for long time for solidification of the epoxy resin after positioning and thus the composite insulator fitting deviates during the glue injection and solidification process to cause poor product positioning precision is solved. The entrance depth of the composite insulator fitting into the positioning slot is controlled and the composite insulator fitting is solidified by using the epoxy resin that is especially for a fill-in way and has a good insulating performance, so that stability of installation of the composite insulator fitting at the fuse is ensured; and the glue injection efficiency of the composite insulator fitting at the fuse is improved.