The invention discloses a method for preparing light non-sintered ceramsite for road capital construction, construction waste and industrial waste serve as main materials, quick lime, desulfurization gypsum, portland cement, ferrous sulfide and rice hull ash serve as auxiliary elements, sodium sulfate, loess, fluorite powder, sodium pyrophosphate, potassiam polyoxyethylene laurylether phosphate, nanometer aluminum oxide and nano zirconium silicate serve as additives, and the method includes the steps of preparing materials, mixing, pelleting forming and steam curing. The apparent density of the prepared non-sintered ceramsites is lower than 1.3 g/cm<3>.