The invention belongs to the technical field of high voltage parallel capacitor monitoring and protection, and particularly relates to a parallel capacitor protection and monitoring integrated methodcomprising the steps that the normal relay protection function is performed by using a relay protection device and the voltage and the current of the high voltage parallel capacitor are measured; calculation of the capacitance value of the high voltage parallel capacitor is completed; the state of the high voltage parallel capacitor is judged by the calculated capacitance value of the capacitor according to the projection criteria so as to complete online monitoring; when the capacitance value change exceeds the regulation, a capacitance alarm signal is transmitted to a transformer substationmonitoring system; and the change information of the harmonic content, overvoltage and overcurrent and the capacitance value is recorded in real time. Protection and online monitoring of the high voltage parallel capacitor are simultaneously realized based on the original relay protection device software and hardware platform without additional arrangement of equipment or changing the primary loop, early warning can be given in the early stage of failure of the parallel capacitor to reduce loss, and the change information of the capacitance value, the harmonic wave, the overvoltage and the overcurrent can be recorded so as to provide the diagnostic basis for damage of the capacitor.