The invention discloses a method for preparing seamless long fiber non-woven fabric based wall cloth. The preparation method comprises the following steps: (1) coating an adhesive onto the surface ofa non-woven fabric, laying long fibers onto the surface of the adhesive, and performing primary drying so as to obtain a primary product; (2) sequentially performing primary treatment and secondary treatment on the primary product so as to obtain a treated product; and (3) compacting the treated product, wherein the temperature of the first treatment is 50-80 DEG C higher than the temperature of the second treatment. The seamless long fiber non-woven fabric based wall cloth has excellent resistance to alternate cooling and heating changes, and particularly does not deform or warp after being subjected to alternate changes of four seasons, namely spring, summer, autumn and winter, in actual application, and the phenomena of bulging and warping of the wall cloth are greatly reduced. Meanwhile, the preparation method has the advantages of simple process and readily available raw materials.