Abstract: In order to adjust the different sensitivity requirements of strain sensor in different working environment and application scenarios, it is of great significance to develop a flexible strain sensor with adjustable sensitivity, however, lack of effective control methods. A crack-structured strain sensor with both high sensitivity and wide range is proposed. By adjusting the proportion of curing agent in polydimethylsiloxane (PDMS), the elastic modulus of Ecoflex/PDMS/graphene (GEP) substrate is controlled within the range of 0.27 MPa~0.85 MPa. By combining composite materials with different elastic moduli to construct the substrate, the precise control of sensor sensitivity is achieved. The research shows that the greater the difference in elastic modulus between the two regions of the substrate, the higher the sensitivity of the sensor, and the length ratio of the two regions of the substrate will also significantly affect the sensitivity of the sensor. The sensitivity GF of the sensor constructed with GEP₀ and GEP_(100∶15) reached 52597, 4880, and 21579 in the strain ranges of 0-2.98%, 2.98%-34.23%, and 34.23%-50%, respectively. The proposed strain sensor with gradient elastic modulus substrate has good anti-environmental interference characteristics, dynamic response characteristics and cyclic stability. It is applied to the monitoring of four motion states and the recognition of five gestures., which can accurately identify the motion status at different joints. Several specifications of sensors can be combined to achieve efficient collaboration, and has stable and obvious real-time signal response. This novel structural design provides a new way for the development of high performance flexible strain sensors.