An　indoor　thermal　environment　is　affected　by　various　heat　elements,　such　as　heat　transfer　through　walls,　solar　radiation,　and　heat　emissions　from　people,　lighting　and　equipment.　To　promote　both　local　thermal　comfort　and　building　energy　efficiency,　demand-oriented　ventilation　(such　as　personalized　ventilation)　has　been　developed.　When　using　this　method,　a　good　understanding　on　indoor　temperature　distribution　becomes　necessary.　For　this　purpose,　an　index　known　as　Contribution　Ratio　of　Indoor　Climate　(CRI)　has　been　developed　through　extraction　from　the　calculation　results　of　Computational　Fluid　Dynamics　(CFD).　This　index　can　be　used　to　analyze　the　independent　contribution　of　each　heat　element　to　indoor　temperature　distribution.　In　this　paper,　a　complete　and　detailed　introduction　of　the　CRI　is　given,　including　its　basic　premises,　definitions,　and　mathematical　meaning.　Particularly,　calculation　method　of　the　CRI　in　natural　convection　airflow　fields　is　further　developed.　Two　cases　(forced　and　natural　convection　airflow　fields)　have　been　carried　out　in　different　scenarios,　with　results　showing　that　the　CRI　of　a　heat　source　had　higher　values　in　the　area　around　itself.　Also,　it　had　a　larger　influence　range　in　forced　convection　airflow　field　because　of　the　convective　airflow,　while　relatively　larger　CRI　values　only　appear　in　the　area　above　the　heat　source　in　the　natural　convection　airflow　field　because　of　the　heat　plume.　As　a　useful　index　for　understanding　the　form　of　indoor　temperature　field,　the　CRI　has　guiding　significance　for　regulating　air-conditioning/ventilation　systems　to　build　better　indoor　thermal　environment.　©　2021