An immunoassay cartridge for sensing at least one analyte in a biological sample is disclosed. The immunoassay cartridge comprises a supporting plate, a reaction cavity made within the supporting plate and having at least one analyte-binding molecule immobilized therein, a sample receiving end connected to the reaction cavity to allow the biological sample to flow into the reaction cavity for forming at least one complex of the analyte and the analyte-binding molecule, a first package containing a recognizing molecule, a first channel communicating the first package and the reaction cavity to allow the recognizing molecule to flow into the reaction cavity for forming a first product of the complex and the complex-binding molecule, a second package containing a buffer solution and a second channel communicating the second package and the reaction cavity to allow the buffer solution to flow into the reaction cavity.