Abstract: In this article we analyze the influences of the abnormity of tropical circulation systems on sustained rainstorm in the Huaihe River basin in June and July of 2003 by using the stream filed in the high and low levels and the index of tropical monsoon. The analysis shows that: the rainstorm has close relationship with northward advancing airflow from the Southern Hemisphere; it was the abnormal strong divergent and convergent air current in the upper and lower levels that offered available conditions to the abnormal rainfall between the Yellow River and the Yangtze River; the outbreak date of South China Sea Summer Monsoon in 2003 was later than normal and the tropical monsoon was weaker than normal, its monthly change was like 1991, and this is the circulation factor for the rainfall to sustain in the Huaihe River basin.