Abstract: In view of the incompatibility of PET material with the standard microfabrication due to its low intolerance to high temperature, an effective fabrication process including lithography, metal deposition and reactive ion etching have been developed which paves the way for direct micro processing on PET. Based on such a method, thin film graphene layer was grown and transferred to 0.5 mm thick PET substrate and the graphene strain sensor was successfully fabricated. According to the measurement results, the piezoresistive gauge factor of the graphene can be estimated about 1.3, which is in good accordance with the value given in literature. Such fabrication method can also be applied in the domain where flexible micro devices are required.