The invention relates to the field of touch sensors, in particular to a capacitive flexible touch sensor and a manufacturing method thereof. The touch sensor comprises a plurality of sensing units which are arranged in a manner of M rows * N columns, and each sensing unit comprises a surface protruding layer, a floating polar plate, a dielectric layer, a first lower-layer capacitor polar plate, asecond lower-layer capacitor polar plate, a lower-layer substrate, a first electrode and a second electrode that are successively attached and connected, and the first lower-layer capacitor polar plate and the second lower-layer capacitor polar plate are arranged on the same surface of the lower-layer substrate respectively, and the problem that in the prior art, the capacitor polar plates must belocated on the two different planes which are opposite to each other, and are easy to be damaged due to excessive stress during use is solved. Meanwhile, the touch sensor provided is mainly preparedfrom a PDMS material and a PI material, the flexibility of the whole sensor is large, and the sensor can be installed on a mechanical arm with different radians.