Embodiments of the present invention disclose a data compression method and apparatus. The method comprises: a terminal device receiving small data transmission (SDT) configuration information from a network side device, the SDT configuration information being used for instructing the terminal device to perform SDT, determining a target data compression area, and in response to the terminal device being located in the target data compression area, executing the data compression while performing SDT. In this way, the terminal device can perform data compression in the target data compression area while performing SDT, thereby improving the performance of data transmission.