To improve the resolution and Signal to Noise Ratio(SNR) of seismic signals, the sweeping mode of pseudo-random code of a seismic vibrator was investigated. The sweeping mode of binary pseudo-random code was discussed, then a new sweeping mode for ternary pseudo-random code was presented. The principle of the pseudo-random code was researched and how to generate the pseudo-random code was given. Based on the obtained pseudo-random code, a pseudo-random code sequence was designed for practical applications. Furthermore, a signal generator of ternary sweeping for the pseudo-random code was embedded into the vibrator, and tested results show that modulation frequency has significant effects on the final self-correlation results. Analysis results on self-correlation function indicate that the SNR obtained from the sweeping mode of ternary pseudo-random code has been improved by 9% as compared with that of the sweeping mode of binary pseudo-random code, which means that obtained sweeping signals are suitable for the seismic exploration.