The　performance　of　a　modular　robot　joint　is　determined　by　its　structure　and　control　algorithm,　which　is　difficult　to　be　determined　by　theoretical　analysis.　Therefore,　the　hardware　and　software　of　a　robot　joint　performance　test　system　are　designed　in　the　paper.　Firstly,　the　hardware　system　consists　of　a　mechanical　device,　sensors,　and　a　data　acquisition　module.　Secondly,　the　software　system　is　developed　based　on　the　LabVIEW　programming　platform,　which　mainly　includes　a　performance　evaluation　module　and　a　human-computer　interaction　module.　The　performance　of　the　robot　joint　such　as　output　rated　speed,　output　rated　torque,　output　speed-torque　characteristic　curve,　repeated　positioning　accuracy,　back　clearance,　torsional　stiffness,　and　transmission　ratio　can　be　tested.　Finally,　the　function　and　feasibility　of　the　system　are　verified　by　experiments,　which　can　meet　the　requirements　of　modular　joint　performance　testing.