The present invention provides a network optimization system, device, and method, including: determining, by a radio resource management functional entity, radio resource statistical data that is based on a TTI time granularity, acquiring radio resource configuration information, and managing a radio resource of a cell in which the radio resource management functional entity is located; determining, by a distributed optimization functional entity, first time granularity data and a first key performance index KPI, determining first reference configuration information, determining a first optimization plan according to the first statistical data and the first reference configuration information, and optimizing the first KPI; and determining, by a centralized optimization functional entity, second statistical data that is based on a second time granularity, and a second KPI, determining second reference configuration information, determining, according to the second statistical data and the second reference configuration information.