A　Unitized　regenerative　fuel　cell　complete　energies　transition　between　chemical　and　electricity　in　a　unitized　cell,　and　this　characteristic　makes　mode　switching　operations　inevitable　in　real　applications.　In　this　work,　cell　voltage　dynamic　response　during　mode　switching　in　a　URFC　with　parallel　flow　field　is　tested.　Single　flow　direction　in　parallel　flow　field　is　not　suitable　fur　unitized　regenerative　fuel　cells　when　operation　modes　are　switched.　Different　flow　directions　for　different　modes　makes　switching　operations　more　stable.　In　addition,　comparing　with　the　flux　of　purge　gas,　the　time　of　purge　increase　is　more　efficient　to　push　out　the　liquid　water　after　electrolysis　cell　mode　stopping　for　the　startup　fuel　cell　operation.