The invention belongs to the technical field of metallurgy, in particular to a method for preparing a {100} surface developed-texture non-oriented silicon steel thin strip based on thin strip continuous casting. The method comprises the steps of smelting molten steel according to set components, wherein the set components comprise, by weight percentage, 0.002-0.005% of C, 2.2-3.5% of Si, 0.2-0.3% of Mn, less than or equal to 0.005% of Al, 0.08-0.20% of P, 0.002-0.005% of S and the balance Fe and inevitable impurities; (2) carrying out thin-strip continuous casting to form a cast strip with the thickness of 1.5-2.5mm; (3) carrying out one-pass hot rolling under an inert atmosphere condition; (4) carrying out single-stage multi-pass cold rolling on the hot rolled strip after clearing oxide skin of the hot rolled strip; (5) carrying out two-stage annealing on the cold rolled coil; and (6) applying an insulating layer to obtain a high-performance non-oriented silicon steel finished product. The method is based on the thin-strip continuous casting, the low-melting-point element P is added, the segregation characteristic of the P on the surface and the grain boundary is utilized, and therefore the intensity of {100} texture in the finished product plate can be enhanced. The method has the advantages that the technological process is short, the energy is saved, the consumption is reduced, and the anisotropy of the finished product plate can be obviously reduced.