The invention discloses a touch sensor and a preparation method. The touch sensor comprises a substrate, a left electrode, a right electrode, a piezoresistive film, a support layer, a pressure column and a flexible layer, wherein the left electrode and the right electrode are erected on the substrate, and the left electrode and the right electrode are of the same height; the piezoresistive film is covered over the left electrode and the right electrode, and the piezoresistive film is connected with the left electrode and the right electrode; the support layer is covered on the surface of the piezoresistive film; the pressure column is erected on the support layer; and the flexible layer is laid over the pressure column. The touch sensor and the preparation method disclosed by the invention have the advantages of optimizing the performance of the sensor and reducing the manufacturing cost of the sensor on the basis of ensuring the accurate detection of pressure position and size.