This document specifies the monitoring items, monitoring methods, calculation methods and evaluation indicators for the operation status of central air-conditioning systems. This document is applicable to the energy-saving monitoring of the actual operation conditions of the cold source system of the compression type cold water circulation central air-conditioning. This document is not applicable to the energy-saving monitoring of the actual operation conditions of multi-split air-conditioning (heat pump) units and direct-fired lithium bromide absorption chillers.