Biosensor and biological detection method

A biosensor comprises a signal detector and a simulated competition object, wherein the signal detector is provided with a sensing unit for sensing signal change; the surface of the sensing unit is irreversibly connected with a specific identification body of a to-be-detected target object; the simulated competition object comprises nanoparticles and competition molecules fixed on the surfaces of the nanoparticles; the competition molecules and the specific identification body have specific affinity action; and the simulated competition object can form a colloid solution and can be irreversibly captured on the surface of the sensing unit. The invention also provides a biological detection method. According to the biosensor and the biological detection method, which are provided by the invention, convenient electrified simulated competition objection construction on the to-be-detected target object which is uncharged or has low-quantity electricity can be realized, and universal mark-free detection on the to-be-detected target object which is uncharged or has low-quantity electricity is realized through the competitive affinity action.