The expression of microRNA (miR)-26b in ovarian carcinoma tissues, its correlation with clinicopathology, and its effect on diagnostic value and prognosis of ovarian cancer was investigated. A total of 74 patients with ovarian cancer (the study group) and 30 patients with benign ovarian tumors (the control group) in the Affiliated Hospital of Inner Mongolia Medical University from July 2011 to June 2013 were retrospectively analyzed. The expression of miR-26b in ovarian carcinoma tissues was detected by fluorescence reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and the correlation between the expression of miR-26b and the pathological features of ovarian carcinoma tissues and prognosis of patients was analyzed. The expression level of miR-26b in the study group (0.28±0.07) was significantly lower than that in the control group (0.54±0.11; P<0.050). There was no significant correlation between miR-26b expression and age, tumor type, exercise habit, smoking habit of patients with ovarian cancer (P>0.050), but there was close correlation between the miR-26b expression and lymph node metastasis, differentiation degree and pathological stage of patients with ovarian cancer (P<0.001). ROC curve showed that the area under curve (AUC) was 0.839, and when the maximum cut-off value was 0.815, the sensitivity and specificity of miR-26b in diagnosing the ovary was 84.932% and 77.936%, respectively. The 5-year overall survival rate in the low-expression group (61.54%) was significantly lower than that in the high-expression group (84.85; P=0.028). miR-26b is under-expressed in the ovary and has a close relationship with pathological stage, differentiation degree, and lymph node metastasis of ovarian cancer, which indicates that miR-26b is involved in the occurrence and development of ovarian cancer and is expected to be an effective indicator for treatment and diagnosis of ovarian cancer and the prognosis of patients.