Electrochromic　(EC)　technology　has　made　tremendous　progresses　and　demonstrated　potential　applications　in　various　fields　such　as　green　building,　smart　displays,　military　camouflage,　etc.　In　recent　years,　flexible　elec-trochromic　devices　(FECDs)　have　attracted　growing　interests　due　to　their　promising　applications　in　flexible　electronics　and　smart　wearable.　In　spite　of　fascinating　flexibility,　the　construction　of　FECDs　faces　more　challenges　compared　with　their　rigid　analogues　because　of　more　complex　configures　and　assemblies.　Thus,　a　comprehensive　review　is　presented　here　to　provide　guidance　for　developing　high-performance　FECDs.　In　this　review,　the　core　components　of　FECD　and　their　flexible　features　are　firstly　introduced.　Then,　recent　advances　and　progress　in　the　construction　of　FECDs　are　summarized　in　detail　based　on　the　different　EC　materials.　Some　critical　performances　are　presented　and　compared　between　different　devices　to　indicate　the　development　direction　of　both　EC　mate-rials　and　flexible　transparent　electrodes　of　FECDs.　Finally,　some　challenges　encountered　in　the　fabrication　and　operation　of　FECDs　are　discussed　and　corresponding　solutions　are　proposed.　It　is　anticipated　that　this　review　will　provide　new　insights　into　developing　high-performance　flexible　ECDs　toward　applications　in　smart　wearable　and　flexible　electronics.