Taken together, through a human circRNAs-sequencing assay and bioinformatics analyses, we discover that circPLPP4 is significantly upregulated in cisplatin resistant ovarian cancer tissues and that this high circPLPP4 expression promoted ovarian cancer platinum resistance through miR-136/ PIK3R1 signaling axis. The gene discussed is PIK3R1; the disease is ovarian carcinoma.