The invention discloses a method for preparing a high-coercivity rare earth permanent magnetic ribbon with an optimized composition proportion. Firstly, raw materials are weighed according to the chemical molecular general formula of (CexNd1-x)19.0Fe71.5B9.5, wherein x and 1-x in the formula refer to numbers of atoms, and the raw materials include, by atomic percentage, x*19.0% of rare earth Ce, (1-x)*19.0% of rare earth Nd, 71.5% of Fe and 9.5% of B; secondly, master alloy is prepared through electric arc melting, and heat treatment is conducted for 12 days at 600-950 DEG C so that the master alloy can be evenly dispersed; thirdly, the permanent magnetic ribbon is prepared through the melt rapid quenching method. The process is simple, the composition proportion is novel, the method is used for producing rare earth permanent magnetic ribbons, and compared with a traditional composition proportion, coercivity is higher. Besides, high coercivity can also be obtained even after part of Ce takes the place of Nd, the utilization rate of light rare earth can be balanced, and cost for producing rare earth permanent magnetic materials is reduced.