The embodiments of the invention disclose a method, a device and a system for implementing a WebP lossy compression algorithm based on an FPGA heterogeneous acceleration platform. The method comprises the following steps: receiving image data information sent by a host, and saving the image data information to a cache, wherein the image data information is YUV image data information, and the cache is set up in advance by the host; calling a WebP lossy compression algorithm implemented by an FPGA hardware circuit according to a start instruction sent by the host, carrying out compressed encoding on the image data information according to the WebP lossy compression algorithm to get processed image data, and saving calculated image data to the cache; and returning calculation completion information to the host to enable the host to read the calculated image data from the cache after receiving the calculation completion information. The compression speed is increased and the power consumption is reduced to a certain extent during use.