Intelligent entrance guard system and entrance guard control method by adopting intelligent mobile phone

The invention discloses an intelligent entrance guard system and an entrance guard control method which are suitable for most intelligent mobile phones and are high in response speed and relatively low in cost, and adopt intelligent mobile phones to replace entrance guard cards. Compared with the conventional intelligent entrance guard system, the intelligent entrance guard system has the advantages that a wireless radio frequency card reader is only required to be replaced by an optical card reader, and the modification cost is low. When the intelligent mobile phone is in optical communication with the optical card reader, a mobile phone screen completely covers the surface of the optical card reader, and the leakage of visible light is avoided; and therefore, the safety is relatively high, and the illegal copying is difficult.