The invention discloses a buried pipeline cathode protection method and system, relates to the technical field of buried pipeline protection, and aims at solving the problems that a method for conducting cathode protection on a buried pipeline according to the experience is low in accuracy, and standard operation procedures are lacked. The buried pipeline cathode protection method comprises the steps that the ground potential difference of an initial pipe and the ground potential differences from a first pipe to an nth pipe are obtained; the ground potential difference of a target pipe and a corresponding installation parameter vector are obtained; then, the ground potential difference of the target pipe and the allowed maximum pipe ground potential of the buried pipeline are compared, and when conditions are met, the obtained installation parameter vector corresponding to the ground potential difference of the target pipe is a target result; or otherwise, the number of anodic sacrifice protection devices and the number of forced drainage devices are adjusted till the conditions are met. The buried pipeline cathode protection method is used for optimal arrangement of buried pipeline cathode protection devices.