Agricultural green transformation is essential for high-quality agricultural development and rural modernization, and farmers’ adoption of green production technologies is central to this process. Although many studies have examined such adoption, limited attention has been paid to farmland transfer contract stability. Using survey data from 1211 farm households in Guizhou Province, China, this study examines how farmland transfer contract stability affects farmers’ adoption of green production technologies. Logit and negative binomial models estimate adoption decisions and adoption intensity, while the control function approach and propensity score matching address endogeneity and selection bias. The results show that contract stability significantly increases both the likelihood and intensity of green production technology adoption, with renewal intention exerting the strongest effect. Mechanism analysis indicates that contract stability works mainly by enhancing farmers’ perceived stability of long-term green returns and promoting mechanization investment/service use. Partly substitute for the effect of contract stability on adoption intensity. The effect on adoption intensity is strongest among medium-scale farmers. Cooperatives weaken the effect of transfer duration but strengthen that of renewal intention, while science and technology commissioners complement contract stability, particularly for written contracts and renewal intention. These findings suggest that improving farmland transfer contract systems and coordinating land institutions with green incentive policies can advance agricultural green transformation.