In　this　work,　we　developed　a　method　for　measuring　the　dynamic　interfacial　tension　of　three-phase　emulsion　based　on　microfluidic　devices.　The　interfacial　tension　of　three-phase　emulsion　in　the　flow　process　changes　rapidly　and　is　difficult　to　measure,　which　has　never　been　reported　in　the　previous　literature.　Through　the　geometric　analysis　of　the　structure　of　three-phase　emulsion,　the　MATLAB　program　is　compiled　to　simulate　the　image.　By　combining　the　simulated　images　with　the　high-speed　photographic　images　of　the　flowing　droplet,　the　dynamic　interfacial　tension　during　the　structural　transformation　of　emulsion　is　derived.　This　method　can　obtain　the　interfacial　tension　of　flowing　droplets　in　microchannels　in　real　time,　especially　for　three-phase　emulsion,　and　can　calculate　the　instantaneous　interfacial　tension　at　an　interval　of　4　ms.　The　error　range　of　the　measured　dynamic　interfacial　tension　value　is　not　more　than　0.1　mN/m,　which　is　relatively　accurate.　We　also　use　the　measured　dynamic　interfacial　tension　to　draw　the　Ca-t　image,　which　shows　the　obvious　differences　at　high　and　low　surfactant　concentrations.　This　is　due　to　the　different　mass　transfer　resistance　of　surfactants　at　high　and　low　concentrations.　In　a　short,　this　study　helps　us　to　further　understand　how　surfactants　diffuse　during　the　flow　process　of　three-phase　emulsions,　which　further　helps　us　to　better　regulate　the　emulsions.