In general, if cancer can be earlier detected and treated, the chance of recovery is relatively much higher. Among all advanced molecular diagnostic techniques, silicon nanowire field effect transistor sensors have proven to have extremely high sensitivity and specificity. Through side-wall spacer etch technique which possesses simpler and cheaper process steps to manufacture polycrystalline silicon nanowire field effect transistor sensor. And p16INK4a protein which is related to cervical cancer, is taken as the target of detection. When human is infected with high-risk HPV, p16INK4a protein will be overexpressed. Therefore, we can know the extent of HPV infection by detecting p16INK4a protein, and then assess whether there is the risk of cervical cancer.