Based on monthly mean flow-off data at Tang Naihai and Ge Zhouba . the characteristics of the temporal variations of flow off are analysed. The results indicate that there are periodic variations of high flow and low flow, and there are different characteristics in different places. At Tang Naihai, there are the dominant periods of 7.4 and 18.5 years, and there are the dominant periods of 15. 14 and 7.07 years at Ge Zhouba. The duration of flow-off departure (the signs of departure are same) at Tang Naibai is longer than that at Ge Zhouba, the monthly variability of the flow-off atTang Naibai is larger than that at Ge Zhouba.The monthly variations of multi-years mean flow-off are a single peak characteristic at Ge Zhouba, but at Tang Naihai, the monthly variations of multi-years mean Dow-off are double peaks, the double peak characteristic at Tang Naihai is related to the movement of the West Pacific Subtropical High. At last, the relationship between the flow-off at Tang Naihai and the departure of sod temperature of the area are also analysed, it is found that high flow years correspond to high Soil temperature, and low now years correspond to low soil temperature.