A　composite　of　methylammonium　lead　iodide　perovskite　(MAPbI(3))　and　carbon　dots　is　prepared　under　ultrasound　irradiation.　Characterizations　of　X-ray　diffraction,　Fourier　transform　infrared　spectroscopy,　X-ray　photoelectron　spectroscopy,　transmission　electron　microscopy,　emission　field　scanning　electron　microscopy,　Raman　spectra　and　UV-Vis　diffuse　reflectance　spectroscopy　are　performed.　Excellent　photoelectrochemical　properties　of　prepared　composites　are　examined　by　a　collection　of　measurements　including　photocurrent　density,　open-circuit　potential,　current-voltage　curves,　cyclic　voltammetry　curves　and　Nyquist　plots.　The　results　imply　that　the　as-prepared　composites　exhibit　better　electrochemical　and　photoelectrochemical　properties　as　well　as　stability　than　those　of　blank　MAPbI(3).　The　improved　properties　are　due　to　the　formed　Pb-O-C　bridge　bonds　in　the　composites,　which　can　promote　the　generation　and　transport　of　charge　carriers.　This　work　provides　a　novel　sonochemical　synthesis　strategy　and　investigation　on　the　photoelectrochemical　performance　of　MAPbI(3)/carbon　dots　composites.