Time Slotted Channel Hopping (TSCH) is one of main features of IEEE 802.15.4e standard designed for wireless sensor networks. It improves energy efficiency, network capacity and communication reliability in industrial applications. However, in the joining phase of TSCH network formation, sensor nodes have to remain awake status for a long time till they can reach synchronization. This is the reason which consumes a significant amount of energy. In this paper, we therefore propose a reliable lightweight joining scheme for TSCH network formation to speed up joining operation. The scheme is present in detail through analysis models as well as implementation result in real sensor nodes. Moreover, the comparison with other approaches is also mentioned to show the potential efficiency and better performance of our proposal.