Ovarian cancer is known as a 'silent killer' for women because it is difficult to be diagnosed at early stages. The five-year survival rate of early-stage ovarian cancer is 92%, but at the late stages, drops to only 17%. Several tools have been used for ovarian cancer screening; however, the outcome is still not satisfactory. Therefore, there is a great need to develop a new method to screen ovarian cancer precisely. Recently, BRCA1/2 gene mutations were confirmed to be highly associate with the occurrence of ovarian cancer. Patients with these gene mutations are risky of developing it in their lifetime. Liquid biopsy such as cell-free DNA (cfDNA) is an emerging non-invasive technology that brings information about tumors from the blood. Previous studies have found BRCA1/2 gene mutations in cfDNA could serve a potential tool for the screening and risk assessment of ovarian cancer. Therefore, an integrated microfluidic system was developed in this work to extract cfDNA from patients' plasma and BRCA1/2 gene mutations were verified automatically, which can provide clinicians a convenient way for risk assessment.