We proposed a portable molecular diagnostic tool implemented by CMOS and Microfluidic technology for the early HIV diagnosis. Our system diagnoses HIV by detecting the P24 antigen concentration in blood sample. We labeled P24 antigens with chemiluminescence signal, which can be detected by our CMOS photon detector. We designed the single photon avalanche diode (SPAD) with single molecule sensitivity, which can help to diagnosis HIV patient earlier, thus increases the chance of cure and reduce the change of further infection spread. To make the system reusable, we use the 10 um diameter magnetic beads as the assay substrate, which can be coated with the anti-P24 antibodies. These magnetic beads can be delivered through microfluidic channels to the sensing area. Then they can catch p24 antigens from the blood sample and generate chemiluminescence signal. After the test, the magnetic beads can be easily washed away, and the system can be reused.