This　paper　initially　depicted　on　the　energy　consumption　of　air　conditioning　systems　in　Beijing　subway　stations.　An　investigation　was　conducted　among　ten　underground　subway　stations　to　the　examination　of　practical　operation　conditions　of　their　cooling　units.　The　overall　field　testing　included　information　such　as　air　conditioning　system　formation,　equipment　types,　system　operation　parameters,　energy　consumption　and　system　operation　efficiency.　The　results　showed　that　the　COP　value　of　refrigerators　in　the　tested　subway　stations　were　generally　high　at　about　4.4　in　average.　Nevertheless,　the　mean　EER　and　SCOP　values　were　nearly　27%　and　48%　lower　than　the　average　COP　value　due　to　the　large　amount　of　energy　consumption　in　water　pumps,　cooling　towers　and　fans.　There　was　a　big　difference　among　each　station　in　terms　of　the　instantaneous　power　consumption　of　air　conditioning　systems.　The　most　energy　consuming　station　was　nearly　seven　times　higher　than　the　least　one.　It　was　observed　that　there　was　a　lack　of　maintenance　and　system　operation　strategy　for　these　underground　air　condition　systems.　A　promising　potential　for　energy　saving　was　found　out　within　the　air　conditioning　systems　in　Beijing　subway　stations.　(C)　2017　The　Authors.　Published　by　Elsevier　Ltd.