The disclosure provides a sleeving assembly of a heat shrink tube, a fastening device, a heating fastening system and a method thereof. The assembly comprises a driving member provided with driven claws; and the driven claws can be opened or closed under the effect of the driving member. Support frames are arranged at the two driven claws respectively and each support frame at least includes an arc structure facing the outer side; clamping members are arranged at the same horizontal line positions of the support frames; and the space between the two clamping members can be adjusted. Accordingto the disclosure, automatic sleeving and fastening of the heat shrink tube can be realized; the manpower investment is reduced; and compared with the manual sleeving and heating fastening, the provided heating fastening mode has high safety and reliability.