Multi-timescale oscillating features of δ¹⁸O and glacial accumulation are approached by using wavelet analysis technique. We found that the warming of recent 100 years is only one of normal fluctuations under the background of the last 1700 years on inter-decadal time-scale. On century time-scale, however, the recent 100 years warming is the strongest, the three cold stages of the Little Ice Age occurred remarkably, but the Medieval Warm Period didn't take place. On the combination of temperature and precipitation, all four climatic types such as warm-wet, warm-dry, cold-wet and cold-dry appeared whether on inter-decadal or on century and millennium time scales. In addition, on the century time-scale, around the 800's A. D. was one key transition period of climatic change, the climate before the period was characterized by warm-dry and cold-wet type and warm-wet and cold-dry after the period. With the transition of climatic condition, the 200a period or so changed too. Its power was not obvious before the 800's but very strong afterwards with 95% confidence level.