Embodiments of the present disclosure provide a network optimization method and a network optimization device. The method includes: acquiring, in a first time segment, a first network status parameter that is determined according to M groups of network status parameters of at least one target cell, and acquiring a first CP that is determined according to M groups of cell control parameters CPs of the target cell, where the network status parameters include a key performance parameter KPI and a cell measurement parameter, determining, according to the first network status parameter and from a first entry that records a mapping relationship between a network status parameter and a security status, a security status of the target cell in the first time segment; and performing network optimization on the target cell according to the security status of the target cell in the first time segment.