The invention discloses a method for preparing a thermal recovery casing material from nano rare-earth oxides based on strain design. The method comprises the following steps: melting low-alloy thermal resistant steel, adding nano rare-earth oxide powder, performing homogenization and solid dissolution treatment, and casting so as to obtain steel ingots, wherein the mass percentage of the nano rare-earth oxides in the steel ingots is 0.2-2.0%; performing control rolling and cold control thermal processing treatment on the steel ingots, and further performing quenched-tempered heat treatment, thereby obtaining the thermal recovery casing material based on strain design. The method aims to common casing damage problems of thickened oil steam thermal recovery wells and is a casing column design method based on strain design, and thickened oil well exploration 90SH thermal recovery casing material within a well depth range of 600-1200m. By adopting the method, solid technical supports aremade for thermal recovery well casing damage treatment and safe and efficient development of thickened oil resources.