In　this　study,　the　cell　performance　of　nonuniform　depth　and　conventional　straight　channel　in　a　unitized　regenerative　fuel　cell　(URFC)　is　compared.　Various　shapes　of　oxygen-side　channel　cases　are　also　proposed.　Several　parameters,　such　as　the　distribution　of　reactants　and　products　and　current　density　and　powers　in　fuel　cell　(FC)　and　electrolytic　cell　(EC)　modes,　are　investigated.　A　steady-state　model　of　two-dimensional,　two-phase,　nonisothermal,　and　coupled　electrochemical　reaction　is　developed.　Five　oxygen-side　channel　shapes　are　also　designed,　in　which　the　depth　along　the　flow　direction　is　narrowed.　Result　shows　that　narrowing　the　average　channel　depth　can　promote　and　guide　the　reactant　transfer　to　the　catalyst　layer　and　avoid　the　blocking　of　the　production.　Thus,　in　comparison　with　the　conventional　channel,　the　cell　performances　of　nonuniform　depth　and　shallow　straight　channel　cases　are　improved　in　both　modes.　In　addition,　with　the　decrease　of　average　channel　depth,　the　temperature　uniformity　gets　better,　which　is　also　conductive　to　the　improvement　of　cell　performance.　Furthermore,　in　FC　mode　at　low　voltage　and　EC　mode,　the　cell　net　power　basically　increases　with　the　decrease　of　the　average　channel　depth　ratio.　And　when　the　average　channel　depth　is　the　same,　the　net　power　of　straight　channel　is　always　lower　than　nonuniform　depth　case.　This　study　introduces　the　round-trip　energy　efficiency　as　an　evaluation　indicator　of　URFC.　This　efficiency　can　be　increased　by　improving　the　cell　performance　of　both　modes,　especially　at　high　current　density.