In　overall　water　splitting,　oxygen　evolution　reaction　is　a　rate-determining　step　due　to　its　complex　reaction　processes　with　sluggish　kinetics,　so　design　of　bifunctional　electrocatalyst　with　elaborated　structure　to　improve　the　oxygen　evolution　reaction　performance　is　critical　to　their　efficient　application　in　overall　water　splitting.　Here　bifunctional　CoMoS4/Ni3S2　nanostructures　are　in　situ　synthesized　by　a　self-templating　strategy,　and　the　morphology　control　of　the　CoMoS4　outlayer　is　simultaneously　achieved　through　a　unique　evolution　from　CoMoO4　nanocolumns　array　to　hollow　CoMoS4　nanosheets　array　with　porous　structure.　Benefited　from　the　synergistic　effect　of　Ni3S2　interlayer,　as　obtained　electrode　exhibits　greatly　enhanced　oxygen　evolution　activity　than　single　CoMoS4　electrode　with　well-preserved　hydrogen　evolution　activity.　It,　together　with　the　three-dimensional　topographic　structure　of　CoMoS4　outlayer　with　high　active　areas,　offers　a　rather　low　cell　voltage　(1.568　V@　10　mA　cm(-2))　for　overall　water　splitting　in　a　two-electrode　system.　Accordingly,　our　results　may　open　new　opportunities　to　explore　hybrid　nanostructures　as　efficient　bifunctional　electrocatalyst　for　overall　water　splitting.