To solve plateau adaptability problems of low-speed roll terminal guidance projectile, flight characteristics of low-speed roll terminal guidance projectile at different altitude were researched. Changes of environment characteristics, rotational speed, overload, missile gain and damping characteristics of the terminal-guidance projectile at high altitude were analyzed. The plateau adaptability modification approaches for the low-speed roll terminal-guidance projectile were provided based on the analysis results. The analysis results and modification approaches' availability were verified by trajectory simulation of one low-speed roll terminal guidance projectile. The modification approaches can provide reference for plateau adaptability of low-speed roll terminal-guidance projectile design and modification.