The rapid detection of bacterial pathogens is very important for medical diagnostics, biosecurity, transportation and the prevention of global pandemics. Here graphene quantum dots (GQDs) are prepared by using citric acid and ethylenediamine and hydrothermal as starting materials and synthesis method. Product is characterized by X-ray diffraction analysis, FT-IR spectroscopy, Transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and photoluminescence (PL) spectroscopy. In the following, graphene quantum dots are used as photoluminescence sensor for detecting Staphylococcus aureus and E. coli. It is found that graphene quantum dots are sensitive at the range of 0 to 9×107 range for Staphylococcus aureus and E. coli.