Abstract: To explore the negative effects of continuous cropping on the growth of Lanzhou lily (Lilium davidii var. unicolor), we conducted a pot experiment using soil containing fresh Lanzhou lily stubble and soil from fields where Lanzhou lily had been cultivated for 2 or 4 years. The growth indexes, photosynthetic characteristics, and antioxidant enzyme activity of Lanzhou lily plants were evaluated, and the types and contents of autotoxic substances in soil from fields continuously cropped with Lanzhou lily for 2 or 4 years was analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the growth of Lanzhou lily was inhibited by continuous cropping at the seedling stage, bulb enlargement stage, and maturity stage, and the inhibitory effect increased with increasing number of continuous cropping years. At the same growth stage, with increased number of continuous cropping years, the activity of catalase and superoxide dismutase decreased, the activity of peroxidase increased and then decreased, the malondialdehyde content increased, the total chlorophyll content, net photosynthetic rate, stomatal conductance, and transpiration rate decreased gradually, and the intercellular CO₂ concentration increased. We identified 9 compounds in soil containing stubble, and 15 and 17 compounds in soil where Lanzhou lily had been continuously cropped for 2 and 4 years, respectively. These compounds included 2, 3-butanediol, dioctyl isophthalate, 2, 2'-methylenebis-(4-methyl-6-tert-butylphenol), and dioctyl terephthalate. The highest contents of dioctyl terephthalate were in soil where Lanzhou lily was continuously cropped for 2 and 4 years (33.24% and 41.43%, respectively). Continuous cropping inhibited the growth of Lanzhou lily by affecting its photosynthetic capacity and disrupting the metabolic balance of antioxidant enzymes, ultimately leading to reduced performance under continuous cropping. The autotoxicity of several secondary metabolites that accumulated under continuous cropping was one of the main causes of the reduced performance of Lanzhou lily.