According to the repeatability and controllability of artificial active source, encoding seismic source can be used effectively to improve the capability of artificial source exploration depth and detection distance. In this paper, the authors studied the encoding and decoding method of active seismic source exploration, and mainly did the following work: ① the analysis of the basic principles of encoding seismic source. The coded method can increase the range of the target and reduce side-lobe energy with correlation; ② the study of three source encoding methods, and make the comparison. The authors have designed coded source which can be fired repeatedly in different time intervals with different energies, and coded seismic source can reduce autocorrelation side-lobes. Signals can be detected with better sensitivity in the time interval after the first autocorrelation peak and before the first periodic side-lobe; ③ the study of the principle of iterative correlation method for decoding. The encoding method can significantly improve the seismic exploration capability. It is proved that researchers can obtain a large detection range and high resolution using encoding method with small energy source.