D ue to th e w ater diversion and d rain ag e pro ject ach iev em en ts, and local w ater reso u rces regulation, th e changes hav e ta k en p lac e in the w estern area of T aihu I^ike basin. B ased on the d ata of p re c ip itatio n , w ater diversion and drain ag e, a n d net inflow in ihe w estem a re a of T aihu I^ k e du rin g 1986—2 0 1 0 , the hydrological elem en ts variation c h a rac teristic s w ere analyzed by using th e M a n n -K e n d all testin g , w avelet analysis, and m oving t-te s t te ch n iq u e . T h e resu lts show that the in creasin g tren d s of th e an n u al and flood season precip itatio n a re not obvious, w hile th e net w ater diversion and inflow into th e w estem a rea of T aihu I^ake in creased significantly for d ifferent tim e scales. T h e significant m utation po ints of an n u al riel inflow o cc u rre d in 1997, 1 9 9 9 ,2 0 0 1 and 2 0 0 6 , in d icatin g that the first was in fluenced hy th e an n u al p recip itatio n m utation, the secon d w as in fluenced by the w ater diversion and d rain ag e am o un t, w hile the last two w ere effected by the w ater diversion prom otion, and hydrom etric gauging sch em e a d ju stm e n ts. In addition , the in creasin g net inflow also has relatio nsh ip w ith runoff yield cind flow c o n c en tratio n variation cau sed by land u se ch an g es.