Infectious　disease　hospitals　must　maintain　pressure　differences　among　rooms　to　direct　the　airflow　toward　the　negative　pressure　isolation　ward　(NPIW)　to　prevent　the　spread　of　airborne　pathogens.　However,　their　values　cannot　be　maintained　easily　in　dynamic　situations,　especially　when　the　door　to　the　isolation　room　is　open.　There　is　a　lack　of　guidelines　for　how　to　cope　with　this　situation.　A　variable　air　volume　(VAV)　damper　is　set　in　the　exhaust　duct　of　the　NPIW　attempts　to　achieve　active　control　by　VAV　but　is　often　set　to　deliver　constant　air　volume　(CAV)　because　of　a　lack　of　confidence　in　its　controllability.　In　this　study,　models　based　on　a　real　infectious　disease　hospital　are　built　and　verified　by　the　multizone　model　on　Modelica.　An　appropriate　active　pressure　difference　control　strategy　for　VAVs　in　NPIW　is　explored　and　it　is　applied　in　a　floor　of　hospital　model　to　analyze　the　influence　of　pressure　differences　among　multiple　rooms　by　VAV　operation.　The　results　show　that　the　pressure　difference　deviations　can　be　reduced　by　9.98%-25.73%　for　different　leakage　paths　of　the　isolation　room　with　this　control　strategy.　The　pressure　differences　among　hospital　are　stable　during　the　VAV　operation　in　the　usual　dynamic　scenario.　The　airtightness　of　the　door　at　zones　junctions　and　external　windows　needs　to　be　reduced　to　strengthen　their　anti-interference　ability　of　pressure　difference.　This　study　fills　the　gap　of　guidelines　and　provides　a　reference　for　the　application　of　VAVs　for　active　pressure　difference　control　in　infectious　disease　hospitals.