Abstract: In offshore oil and gas exploration, seismic source design is the key to ensure good pickup of signals, for which air gun has become the most widely used excitation source in marine exploration due to its reliable quality, flexible combination, safety, and environmental protection. However, with the complexity of exploration environment, conventional excited wavelet of planar array is no longer to satisfy high-resolution exploration. Therefore, based on the stereoscopic array, we analyzed the relationship between wavelet signals and time of gas guns with different capacities. By optimizing the sinking depth, the amplitudes generated by the excitation of single gun with different capacities are superimposed in the same phase during receiving to broaden the frequency band and suppress the notch effect and improve the seismic source performance. By comparing the properties of the optimized stereoscopic array with the conventional array, it was proved that the broadband stereo air gun array had stronger amplitude energy and wider effective frequency band, which could suppress the notch effect obviously, and achieved better recognition results at complex geological targets.