The invention discloses porous adsorption type ceramsite and a preparation method thereof, belonging to the technical field of solid waste comprehensive utilization. The porous adsorption type ceramsite is prepared from the following raw materials in parts by weight: 65-80 parts of municipal sludge, 1-3 parts of vegetable sponge, 10-20 parts of cement clinker and 10-20 parts of coal ash. The preparation process of the porous adsorption type ceramsite comprises the following steps of raw material treatment, blending, pelleting, carrying out pyrolysis and dry distillation and roasting. The vegetable sponge with a certain network structure is added during preparation of ceramsite, so as to prevent the ceramsite from cracking and enabling the inside of the ceramsite to form communicated pores; the ceramsite has high strength, high-temperature resistance, acid-base resistance and good adsorptive property, the resource utilization of the solid wastes is realized, a new way for solving the environment pollution problem caused by solid wastes is found, and the porous adsorption type ceramsite can be used for sewage purification, industrial wastewater adsorption, oil well filling and the like, and has wide application prospect.