Method for acquiring voltage-current characteristic curve of plasma

The invention relates to a method for acquiring a voltage-current characteristic curve of plasma. The method is characterized in that plasma parameters are probed by using a Langmuir probe under the condition of radio-frequency discharge mode; a point to be probed is probed by the Langmuir probe under the control of a scanning voltage to acquire sampling values of the parameters, thereby, the voltage-current characteristic curve of the plasma is acquired, wherein one-time probe working time comprises a plurality of discharge cycles; the stable scanning voltage is applied to the Langmuir probe during the same discharge cycle; and each discharge cycle corresponds to one different scanning voltage.