Ovarian cancer is one of the fatal diseases in women. However, it can be cured if the early-stage diagnosis and suitable treatment is given on time. The goal of the research is to produce nano-biosensing technology for early identification of fatal ovarian cancer. In this regard, a rapid and colorimetric nano-biosensor was constructed employing gold nanoparticles to target platelet-derived growth factor (PDGF), a circulating biomarker that is up-regulated in plasma in prevalent ovarian cancer. The findings were supported by spectroscopy analysis and characterized the nanoparticles using SEM (Scanning electron microscopy & XRD (X-ray diffraction). In this proposed principle, gold nanoparticles (AuNPs) are mixed with PDGF specific aptamer and employed to identify PDGF by screening changes in the color as well as absorbance of the Aptamer and AuNPs caused by aggregation. The AuNPs color changes from pinkish to light purple at higher level of concentration. Signal-output exhibited for PDGF was in the linear range of 0.01–10 μg/ml under the optimum conditions. The change in color of gold nanoparticles was seen when the concentration of PDGF was as low as 0.01 μg/ml. Also, the developed technique was successfully applied in artificial serum which have many components of biofluids. The results we presented in this research can imply the practical application of aptamer and AuNPs in cancer diagnosis, exhibiting its benefits of reliability, selectivity, and reproducibility.