The invention relates to a method for preparing a supported palladium catalyst by using different precursors through a photochemistry method and belongs to the field of catalyst preparation technologies. The method comprises the following steps of respectively soaking a carbon nanotube into acetone and a NaOH solution, stirring the soaked carbon nanotube by NH4F solution of 1 mol/L for 6 hours, and naturally cooling to the room temperature after vacuum drying to obtain a carbon nanotube after modified treatment; and preparing a Pd precursor; uniformly mixing the obtained Na2PdCl4 or (NH)2PdCl4 precursor, acetone and polyethylene glycol-400 and diluting to obtain a mixed solution, carrying out ultrasonic treatment on the carbon nanotube after modified treatment and the mixed solution for 5 minutes, continuously stirring for 3-6 hours, irradiating under the ultraviolet light in a stirring process, and lastly, cleaning through distilled water, carrying out vacuum filtration and drying to obtain the supported palladium catalyst. The method combines precursor reduction and loading into one step, the process is simplified while the load dispersity of Pd nanoparticles is better, and furthermore, through Na2PdCl4 and (NH)2PdCl4 two precursors, the PH regulating range of the solution is larger.