The　construction　of　heterojunction　photocatalysts　can　accelerate　the　separation　of　photogenerated　electron-hole　pairs　and　thus　improve　the　photocatalytic　activity.　Herein,　novel　NiSe2/CdS　heterojunctions　were　successfully　constructed　using　an　in　situ　solvothermal　method.　The　as-obtained　NiSe2/CdS　composites　are　composed　of　NiSe2　nanoparticles　grown　in　situ　on　CdS　nanorods.　The　resultant　5　wt　%　NiSe2/CdS　sample　exhibited　good　stability　and　a　high　photocatalytic　H2-production　rate　of　167.1　mmol　g-1　h-1,　which　is　2.7　times　higher　than　that　of　bare　CdS.　The　apparent　quantum　yield　was　1.5%　at　420　nm.　The　enhanced　photocatalytic　activity　can　be　ascribed　to　effective　charge　separation　and　the　charge　fast　transfer　between　CdS　nanorods　and　NiSe2　nanoparticles.　This　work　demonstrates　that　low-cost　NiSe2　can　act　as　a　highly　efficient　cocatalyst　for　rational　design　of　high-performance　photocatalysts.　Copyright　©　2019　American　Chemical　Society.