Ovarian cancer has the highest mortality among gynecologic cancers. The rate of early diagnosis is low and most cases have reached an advanced stage at the initial diagnosis. More than one-third of ovarian cancer patients present a large amount of ascites at the time of diagnosis. Acellular fraction of ovarian cancer ascites richly includes cytokines, proteins, metabolites, and exosomes, constitutes a unique and complicated tumor microenvironment, and influences the biological behavior of tumor cells and the progression of the disease. This paper gives an overview of the acellular fraction of ovarian cancer ascites and its effect on tumor.