Homogeneous　electrocatalytic　reaction　has　been　extensively　applied　in　electrochemical　flow　sensors　especially　for　the　detection　of　non-electroactive　species.　Herein,　homogeneous　electrocatalytic　reaction　is　studied　on　a　rotating　disc　electrode　(RDE)　system　to　mimic　the　forced　convection　in　flow　sensors　in　both　experiments　and　theory.　The　experimental　RDE　voltammogram　reveals　a　pre　plateau　feature　under　the　rotation　frequency　of　25　rpm　and　the　corresponding　theoretical　current–potential　curves　generated　by　2D　axisymmetric　electrochemical　analysis　model　is　in　good　consistency　with　the　experimental　voltammetric　responses.　Based　on　the　same　model,　mediator　and　substrate　concentration　distributions　and　the　diffusion　layer　thicknesses　are　discussed　in　detail.　Moreover,　the　interference　of　direct　electrochemical　oxidation　of　the　substrate　is　investigated　via　the　homogeneous　electrocatalytic　reaction　between　1,1′-ferrocenedicarboxylic　acid　and　L-cysteine　and　the　corresponding　second-order　rate　constant　(372　(mol　m−3)−1　s−1)　is　shown　by　the　modified　model.　Also,　the　influence　of　substrate　diffusion　coefficients　in　homogeneous　electrocatalytic　reaction　is　analyzed　and　the　obtained　transition　point　indicates　the　specific　critical　second-order　rate　constant　for　both　ferroceneacetic　acid　(106.02　(mol　m−3)−1　s−1)　and　1,1′-ferrocenedicarboxylic　acid　(105.36　(mol　m−3)−1　s−1)　as　the　mediator.　At　last,　the　design　principle　of　homogeneous　electrocatalytic　flow　sensor　is　summarized.　©　2021　The　Author(s)