The invention discloses a defense method, a thievery prevention method and a thievery prevention device of a mobile terminal. The defense method, the thievery prevention method and the thievery prevention device of the mobile terminal are used to effectively protect legal rights of a user. The defense method of the mobile terminal includes: after detecting that metal frames on two sides of the mobile terminal are pushed out, controlling the mobile terminal to enter a discharging mode; under the discharging mode, controlling the mobile terminal to output voltage at a set voltage value; applying the voltage at the set voltage value onto an electrode integrated with the metal frames on the two sides of the mobile terminal. The defense method, the thievery prevention method and the thievery prevention device of the mobile terminal can enable the metal frames and the electrode to discharge electricity together, and thereby enlarge discharging power and a discharging range of the mobile terminal. Additionally, after the metal frames are used, a handhold area of the user is a nonmetal area, and therefore personal safety of a legal user can be effectively protected.