A flexible sensor used for touch detection and an application thereof. The flexible sensor having a flexible substrate, at least two conductive layers and a plurality of electrodes, the conductive layers respectively covering two surfaces of the flexible substrate, the electrodes being arranged at two ends of the conductive layers, the conductive layers having a matrix and first conductive particles dispersed within the matrix. The sensor has stable output characteristics and good consistency between individuals, is easy to install, low-cost and highly sensitive, and can replace PVDF piezoelectric thin film sensors for monitoring human heartbeat and breathing state data.