The invention provides a control protection method and system for a power distribution network series capacitor compensation device. The control protection method comprises the following steps of acquiring the physical quantity of the capacitor compensation device; enabling the obtained physical quantity to be substituted into a pre-established fast switch control model, and realizing the controlprotection of the power distribution network series capacitor compensation device; and enabling the fast switch control model to adopt a voltage and power flow automatic switching, capacitor protection or rapid fault identification method for controlling the separation or closing of the fast switch of the power distribution network series capacitor compensation device. According to the control method and system, the risk of overvoltage and magnet resonance is eliminated, and the protection of the internal fault of the capacitor and the rapid fault protection of the power distribution network series capacitor are realized.