Residence security defense system and defense method

The invention discloses a residence security defense system and defense method. The residence security defense system comprises a signal acquisition module, a central control module, an alarm module and a mobile terminal. The signal acquisition module is used for acquiring whether a thief enters a gate and an anti-theft net or not, whether a thief enters the gate is judged, head portraits are collected through a first camera and compared, meanwhile whether a key is inserted or not is judged, if the head portraits accord, and the key is inserted into the gate, an infrared sensor does not work, and alarming and notifying of the mobile terminal are not conducted; and if any one of the two conditions does not accord , the infrared sensor works to judge that a thief enters, and alarm and notification of the mobile terminal are realized. If a thief passes through the anti-theft net, a signal is obtained through the change of the resistor to judge whether the thief enters the anti-theft net or not. According to the