The invention discloses a method for calibrating the linearity of a tested sensor by using continuous charge quantity. The method comprises the steps: injecting a pulse signal of which the charge quantity is increased by the preset step length to the tested sensor; outputting a response signal to the pulse signal through the tested sensor; collecting the response signal through an acquisition unitand sending the response signal to an analysis unit; and analyzing the linearity error of the tested sensor by the analysis unit. The linearity of the partial discharge sensor in a wide range of charge quantity intervals can be more accurately calculated.