Abstract: With corresponding data from 1961 to 2001,the relationship between rainfall in May over Longitudinal Range-Gorge Region(LRGR) and previous and current tropical sea surface temperature anomaly(SSTa) was studied with principal component analysis and canonical correlation analysis.The results show that there is the closest relation between the rainfall in May and current tropical SSTa;there is closer relation between the rainfall in May and tropical SSTa in previous January and February.The correlation between the rainfall in May and tropical SSTa over western Pacific is positive,but that over tropical eastern Pacific is negative,which implies that,when walker cell over Pacific is stronger,the May rainfall over LGRG increases.On the contrary,when walker cell over Pacific is weaker,the opposite condition will happen.