Through the investigation of the difference of approximate entropy (ApEn) and Hilbert-Huang Transform Marginal spectrum entropy (HHTMSEn) of the Electroencephalogram (EEG) signals of specific low back pain (SLBP) patients before and after the massage, we wanted to reveal the impact of the massage in the brain, and provided the basis for the massage treatment of SLBP patients. We recruited twenty-six SLBP patients and collected their spontaneous EEG signals before and after the massage. Firstly, we analyzed the ApEn and HHTMSEn of fourteen channels before and after the massage, and results showed that values of ApEn and HHTMSEn after the massage were less than the values before the massage significantly. And then, we extracted δ, θ, α and β rhythms of the EEG signal, and analyzed the ApEn and HHTMSEn of the four rhythms before and after the massage. The results showed that the ApEn values of δ and α rhythm after the massage were significantly less than the values before the massage, and the HHTMSEn values of β rhythms were significantly less than the values before the massage. The results of this study suggested the complexity of EEG signals was reduced with the relief of the pain after the massage therapy, and the change of pain of the SLBP patients was closely related to the change of the rhythms of the brain in the massage therapy, and the ApEn and the HHTMSEn features could serve as a base for quantitative assessment of SLBP condition after the massage therapy.