In seismic exploration, converted wave data contains important stratigraphic and structural information. Common conversion point (CCP) gather extraction is a key step in converted wave seismic data processing, which has a great impact on velocity modeling and migration imaging. The traditional CCP selection and sorting extraction method mainly adopts the whole trace selection and sorting method, typically the asymptotic conversion point (ACP) gather extraction. This method is able to better meet the imaging requirement of deep strata through the classification strategy of asymptotic approximation, but it cannot image the shallow strata well. To solve the above problems, a new spatiotemporally variable conversion point gather extraction method is proposed. The method gives the mapping relationship between the input converted wave data and the output CCP gather by accurately calculating the spatial locations of the CCP and combining the converted wave two-way traveltime. This strategy allows the reflected seismic signals to be mapped to more accurate spatialtemporal locations, which can effectively deal with the variations of converted waves in asymmetric propagation paths and significantly improve the quality of the CCP gather extraction. The verification results of numerical simulation and field data show that the CCP gather extraction method proposed in this article has demonstrated good application effects in application. The new method not only improves the utilization of data, but also enhances the imaging accuracy of shallow layers and geological structures in complex areas. The new method can be treated as an effective gather extraction tool for seismic converted wave data processing.