The relationship between coral growth rate and sea surface temperature anomaly (SSTA) was used to reconstruct the SSTA in the central South China Sea Since 1780. Our reconstruction shows that SSTA over the period 1780 - 1890,which correspond to the latter part of Little Ice Age,was cold relatively,the average SSTA was - 0.2℃,the coldest SSTA was - 1℃ in 1837. After 1890,the SSTA increased most fast between 1971 to 1998,the highest SSTA was 2℃ in 1998,but there was a downward trend after 1998,which is basically synchronous with the change of land temperature in Northern Hemisphere. The spectral analysis shows a significant period of 26 - 34 a for the SSTA in the central of South China Sea,with the phase transitions correspond to the decadal shifts of the Pacific Decadal Oscillation. The wavelet analysis indicated that the interdecadal oscillation of the SSTA in the central South China Sea was not stable over the past 234 years. After entering the Current Warm Period,the interdecadal variability has enhanced distinctly,which may be related to the changes in the internal variability of the ocean associated with the global warming. Our result,together with the change in the decadal-scale SST variability of the tropical southwest Pacific in the 1890,suggested that the internal variability of the tropical Pacific has changed since 1890.