Nanocrystalline　InOOH　photocatalyst　was　synthesized　from　In　(NO3)(3)　and　ethylenediamine　via　a　solvothermal　method.　The　obtained　sample　was　characterized　by　X-ray　diffraction(XRD),　UV-Vis　diffuse　reflectance　spectroscopy(DRS),　scanning　electron　microscopy(SEM)　and　transmission　electron　microscopy　(TEM).　InOOH　can　degrade　rhodamine　B(RhB)　to　CO2　and　H2O　under　UV　irradiation,　while　it　can　only　degrade　RIM　to　de-ethylated　product　under　visible-light　irradiation.　The　photocatalytic　degradation　of　RhB　follows　two　different　reaction　mechanisms　under　UV　light　and　visible　light.