Abstract: The exploration of Mesozoic strata in the Chaoshan Sag of the Pearl River Mouth Basin in the South China Sea faces challenges such as severe seismic wave energy shielding and strong multiple-wave development. This study introduces a wide-line acquisition and processing approach to perform integrated wide-line processing on two 2D seismic lines acquired in proximity but in different years. Key issues during processing, including common midpoint (CMP) bin definitions, multiple suppressions, and imaging methods, are discussed. Noise suppression, multiple attenuation, and consistency processing for the time shifts, amplitudes, frequencies, and phases were performed. The 2D pre-stack depth migration method was selected for imaging and yielded favorable results. The results indicate that compared to the original 2D data, the processed data after integrated wide-line processing enhanced the effective reflection energy in the middle-deep layers, improved the multiple wave suppression effect, broadened frequency bands with richer low-frequency components, improved the signal-to-noise ratio (SNR), increased accuracy in velocity analysis, clearer wave group characteristics of the target horizons, and better continuity of events. This method provides a valuable reference for leveraging historical data to improve middle-deep layer imaging and explores a new approach to wide-line processing. This represents an economical and practical technology for middle- to deep-layer exploration in offshore areas with abundant 2D seismic data.