A method and a system for data compression are provided. The method may include: obtaining scanning data to be compressed; compressing the scanning data using a first compression method and a second compression method to obtain a first compressed data and a second compressed data respectively, where a compression ratio of the first compressed data is lower than a compression ratio of the second compressed data; and determining whether the compression ratio of the first compressed data meets a predetermined compression ratio requirement, if yes, determining the first compressed data as a compression result data corresponding to the scanning data, if no, determining the second compressed data as a compression result data corresponding to the scanning data. Scanning data compressed by the method or the system can meet target compression requirements.