In wireless sensor network (WSN), the design of routing protocols focuses mainly on the energy efficiency based on the application of the network. Over the past years, researchers developed many solutions to protract the life expectancy of the network by reducing the consumption of energy by each node. One of the main approaches is the usage of sink in mobility; this reduces the hotspot problem and energy consumption. Aiming at this problem, the paper proposes a new routing algorithm which supports the sink mobility with energy aware tree-based sink relocation routing protocol (TBSR) using adaptive fuzzy decision-making approach (AF-MADM). In TBSR, a self -organized routing tree is formed, which reduces the consumption of energy. In the beginning, the clustering process is employed using fuzzy possibilistic C-means (FPCM) algorithm. Further, the fuzzy analytic hierarchy process (FAHP) with multiplicative exponential weighting model is developed for optimal decision making to select the root node. Then the selected root node creates a routing tree based on the distance and energy of the sensor nodes. Then each node uses its cluster information and the distance of the neighbors to select the parent node. For relocating the sink node, the proposed protocol calculates the energy along with hop count and path capacity. These methods make TBSR an energetic and analogous protocol. Results show that the proposed TBSR improves on the energy consumption and the lifetime of the network compared with existing protocols. The simulation is carried out in OMNET++ platform. © 2021 John Wiley & Sons Ltd.