With the advent of the era of big data and Internet of Things, wearable electronics are becoming more imperative than ever before, which prompts the continuous and fruitful research on wearable sensors and sensing network for health and environmental monitoring. This article presents an in-depth overview and review of this fertile area, focusing on sensors and sensing networks for strain, pressure, surface bio-potential, gas and temperature, which are made from low-dimensional carbon nano-materials and their composites. It covers materials, device structures, fabrication, performance and applications. It’s evident that the appropriate and deliberate selection of low-dimensional carbon materials, matrix and substrate materials, and their interactions, as well as effective structural designs, are essential for highly sensitive and stable performance. Finally, the current status of industrial application is presented, possible hindrances for the adaptation of the technology are discussed, and future directions of development are indicated.