The invention discloses a method and a system for supplying power to a mobile terminal. In the method, two power supply channels 1 and 2 of a programmable power supply are used for supplying power supply voltages needed by a battery terminal and a charging terminal of the mobile terminal when the mobile terminal works normally. The method particularly comprises the following steps that: the character that the charging terminal of the mobile terminal also generates startup current when the loaded power supply voltage is insufficient is utilized, and before electricity is supplied to the mobile terminal formally, whether a power supply terminal of the mobile terminal is correctly connected is judged by outputting a test voltage in advance and detecting the startup current, so the power supply safety of the mobile terminal is ensured, the problem that the mobile terminal is damaged due to reverse connection of the power supply terminal is avoided, furthermore, the generation of fault machines is reduced, the production cost is reduced, and the first pass yield rate of production is improved. The method for power supply has a simple design, can provide conveniences for a line operator to make judgments, and is suitable for popularization and application in related mobile products such as mobile phones, MP4 and the like.