A method for reducing current consumption of a mobile terminal is provided. The method includes setting a task as an initial idle task of the mobile terminal for performing a simple infinite loop in a state where all of the effective tasks performed by a program of the mobile terminal are blocked, counting global variable values of the idle task for a predetermined time according to a timer interrupt signal generated by the timer at regular intervals and storing the global variable values of the idle task as a reference value of an idle task of a program of the mobile terminal, resetting the counted value, measuring by counting the global variable values of the idle task where an effective task occupies the idle task for a predetermined time and storing the global variable values of the idle task as an idle value of the effective task according to a timer interrupt generated every predetermined time by the timer when the program of the mobile terminal performs the effective task, dividing the measured idle value of the effective task by the reference value of the idle task, to thus calculate a program idle rate of the mobile terminal, and storing the program idle rate, and changing a PLL value according to the program idle rate of the mobile terminal and varying a main clock frequency of a CPU of the mobile communication terminal.