The invention provides a method for biological detection, which comprises the following steps of (A) providing a biosensor and a receptor. The biosensor includes two sensing electrodes which are spaced apart from each other, and each of the sensing electrodes has a metal response layer. The receptor disposes on the metal response layer and bond with the metal response layer, and (B) disposing a ligand on the receptor, and applying a pulse voltage that has tunable pulse width and pulse height to the metal response layer, causing in a voltage difference between the two sensing electrodes, and measuring a detection current which generates from the biosensor in the pulse width as to obtain the first sensing indicator. |