1. A method for evaluating network performance, comprising: obtaining statistical data characterizing network performance, wherein the statistical data comprises the number of unknown physical cell identifiers (PCIs) triggered by an event or periodically; and obtaining performance of automatic neighbor relationship adjustment according to the statistical data, or obtaining a degree to which the automatic neighbor relationship adjustment affects the network performance according to the statistical data, wherein the automatic neighbor relationship adjustment is used to automatically discover, add and delete a neighbor cell and the number of unknown PCIs is used to indicate the number of cells with new PCIs found by the automatic neighbor relationship adjustment; wherein one or more data in the statistical data forms a preset condition for measuring whether the automatic neighbor relationship adjustment achieves an operating requirement target or meets a specified requirement of the automatic neighbor relationship adjustment, and the method further comprises: judging whether the automatic neighbor relationship adjustment achieves the operating requirement target according to the preset condition, or measuring a degree to which the automatic neighbor relationship adjustment meets the specified requirement according to the preset condition; if the operating requirement target is achieved or the specified requirement is met, terminating the automatic neighbor relationship adjustment; and if the operating requirement target is not achieved or the specified requirement is not met, activating the automatic neighbor relationship adjustment, or continuing the automatic neighbor relationship adjustment which has been started.