The script of Heroic Little Sisters of the Grassland was originally a fairytale. In the original film script, the Mongolian sisters sing, dance, and play with anthropomorphic sheep. The villain is an evil eagle, who takes the good animals and the sisters to the sky. However, after animators went to Inner Mongolia and sketched from life, they decided to follow a realist and documentary style to truthfully portray the two heroes as news reports did at the time. Animators therefore deleted the anthropomorphic animals that appeared in the original script. The wild eagle is gone, and the sheep in this animated film stop talking and become biological animals that are the property of the people’s commune. Here the animators most likely self-censored their work because as early as 1964 the artistic coercion characteristic of the Cultural Revolution had already begun, with the criticism of several live-action feature films like Zaochun eryue (Early Spring, 1964). In addition, criticism of fantasy and fairytales was even more intensified in the mid-1960s. In November 1965, anthropomorphism, regarded as a way of defaming workers, peasants, soldiers, and children, was officially banned in the Shanghai Animation Film Studio. The release of Heroic Little Sisters of the Grassland in December 1965 was a timely fit.

Heroic Little Sisters of the Grassland was the only cel-animated film made during the Seventeen Years that survived the artistic persecution and was even constantly reproduced as a media fetish in different artistic forms during the Cultural Revolution. As the film traveled into the depth of the Cultural Revolution, the biological animals featured in it continued to disappear radically. In November 1970, the Shanghai People’s Press published a picture book directly adapted from the animated film. Also entitled Heroic Little Sisters of the Grassland, this picture book had the same plot as the animated film. However, in the picture book the role of Chairman Mao becomes more prominent and the emphasis on class struggle is intensified.