The prosperous Shierqiao culture in the Chengdu plain of southwest China was a key component of the Shu civilisation. However, we know little about its subsistence economy. The Longhucun ((sic)(sic)(sic) in Chinese) site of the culture was selected for soil flotation to remedy this. Archaeobotanical research identified 18 plant species, comprising 15 wild plants and three cereal crops, namely rice, foxtail millet, and broomcorn millet. Based on plant remains recovered from 19 pottery kilns and their ash pits, we suggest that wild grasses and timber were utilised as primary fuels. Crop grains were often retrieved in kiln deposits, implying their use not only to manufacture pots, but also probably to perform culinary practices. Rice farming played the most important local role. One rice landrace might be preferentially cultivated judging from its shortness determined by morphometrics. Dryland millet farming was also conducted, although at lesser scale. This pattern of crop cultivation was similar to that of other contemporary sites in the plain, but significantly different from that practiced in marginal areas, probably due to topographic differences. Such a complementary and accommodating mixed rice and millet cultivation was a resilient strategy, sustaining the continued development of the Shu civilisation.