Flexible electronics integrated with stretchable/bendable structures and various microsensors that monitor the temperature, pressure, sweat, bioelectricity, body hydration, etc., have a wide range of applications in the human healthcare sector. The science underlying this technology draws from many research areas, such as information technology, materials science, and structural mechanics, to efficiently and accurately monitor technology for various signals. In this paper, we make a classification and comb to the designs, materials, structures and functions of numerous flexible electronics for signal monitoring in the human healthcare sector. Some perspectives in this field are discussed in the concluding remarks.