Flexible strain sensors are critical to several potential intelligent applications, such as human–machine interfaces, soft robotics, human motion detection, and safety monitoring of components. Stretchable functional materials are important components of strain sensors, and they are still a major challenge for high‐performance strain sensors. Herein, a novel strategy of designing and optimizing a flexible strain sensor by developing topological structure modulated high dielectric elastic nanocomposite is demonstrated. The topological structure produces synergistic effects of space charge enhancement and local electric field modulation, and it gives rise to an ultrahigh dielectric permittivity (113.4, at 1 kHz) and excellent comprehensive electromechanical performance for the dielectric elastic nanocomposite. An interdigital capacitive strain sensor is prepared based on the topological structured elastic dielectric nanocomposite, and it possesses positive capacitance response with strain, which breaks through disadvantages of negative sensitivity and narrow linear range for conventional interdigital strain sensors. The strain sensor achieves high signal‐to‐noise ratio, high positive capacitance response sensitivity of 5.7 pF %–1, and wide linear range (strain from 0.1% to 100%). The high permittivity elastic nanocomposite is capable to fabricate integrated microsensor array, making conditions for detecting local strain of convoluted surfaces and motion states of flexible actuators.

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