Abstract: The present application relates to the technical field of sensors, and in particular, to a flexible piezoresistive sensor and a preparation method thereof. The preparation method includes the following steps: cutting natural wood to obtain wood blocks; removing lignin and hemicellulose from the wood blocks to obtain an initial product; and connecting the initial product to an electrode, and conducting packaging to obtain the flexible piezoresistive sensor. The preparation method has the advantages of a wide range of raw materials, degradability, low cost, simple process, and industrial scale production, and the obtained product features excellent environmental friendliness, biocompatibility, designability, and flexibility, thereby providing a good application potential for a wearable device.