Objective To study the relationship between serum CA125 levels and Child-pugh classification of liver cirrhosis and quantity of ascites. Method A total of 91 patients were studied,consisting of 32 in Child-pugh A, 36 in B , 23 in C;There were 50 patients with ascites and 41 without ascites; serum CA125 level were measured in all patients and in 32 normal persons by ELISA.Results The levels of serum CA125 in liver cirrhosis patients were significantly higher than in controls(P0.01) and in Child-pugh C in B in A, increased gradually with aggravating lesion of the liver(P0.01); Serum CA125 levels in liver cirrhosis with ascites group and with small amount ascites group were significantly higher than without ascites group (P0.01), with middle amount ascites group significantly higher than with small amount ascites group (P0.01), There were without statistics significance between comparison of serum CA125 levels in large amount ascites group and in middle amount ascites group. Conclusion The levels of serum CA125 in liver cirrhosis patients were osculating correlation with lesion of the liver and ascites degree, could serve as a sensitive marker for liver lesion degree and monitoring ascites quantity, were of value to early diagnosis and estimating prognosis for liver cirrhosis patients with ascites.