In this paper, flood/drought runs combined with tunaing points were called flood/drought run-turning points. Consider the flood/drought run-turning points in the historical flood/drought records of the last 500 years as recurrent events.Then, the theory of recurrent events may be applied to the historical records for climatic analysis. Now, let F be flood year with probability P, while D the drought year with probability q. If ε⁺=FFF-FD,then thecri-tical point between F and D is called the positive run-turning point, while the critical point between D and F is called the negative run-turning point, if ε^-=DDD-DF. Let f_n⁽⁺⁾=p (ε⁺ occurs for the first time at thenth trial) and f_n^(-)=p (ε^- occurs for the first time at thenth trial) for n>1 with f₀^(±)=0. Then, mean and variance of the run-turning times were derived by means of generating function, and the calculated results of these parameters at different stations are likely useful in climatic analysis.