A comparison of performance of three different types of graphene biosensors for the detection of prostate specific antigen was reported. Three different graphene structures were synthesized by mechanical exfoliation, microfluidic and self assembly respectively, representing graphene composites from pure to hybrid. Various parameters of different types of graphene biosensors were compared, such as detection limits, sensitivity, stability, etc. Hybridized materials in the graphene composites will change the electrical stability. However, hybrid or decorated materials enhance the absorption of target molecule, which introduce much higher sensitivity and detection limits. As were expected, self assembled graphene biosensor demonstrated the highest detection limits and sensitivity, but showed poor stability. On the other hand, pure graphene and microfluidic induced graphene presented lower detection limits and sensitivity, but better stability due to the absence of hybrid polymer in the graphene composites. The results and discussion demonstrated here can provide a guidance for the design of graphene based biosensors.