Objective This study aims to examine whether and how conservation tillage improves the climate adaptability of grain production， revealing its heterogeneous effects from a dual-dimensional perspective of proactive response and passive adaptation. Methods Based on panel data from 44 sample counties in Heilongjiang Province， China， from 2012 to 2022， a dual-dimensional evaluation framework was established incorporating proactive response and passive adaptation. The Tobit models， system generalized method of moments （GMM）， double machine learning， and spatial Durbin models were employed to empirically test the impacts of conservation tillage on climate adaptability. Results 1） From 2012 to 2022， the climate adaptability of grain production in Heilongjiang Province exhibited an overall evolution pattern of first declining and then rising， with 2017 as a key turning point. Spatially， the pattern evolved from a scattered distribution of high-value areas in the early stage to a distinct east-west differentiation， with high-value areas in the east and low-value areas in the west. 2） Conservation tillage had a significantly positive effect on proactive response， but no significant effect on passive adaptation. The system GMM results showed that the first-order lag term of climate adaptability was significantly positive， indicating that the adaptability improvement showed evident path dependence and dynamic accumulation characteristics. Spatial analysis further demonstrated that the direct and indirect effects of conservation tillage on proactive response were 0.119 and 0.711， respectively， with indirect effect playing a dominant role， indicating a significant spatial spillover effect. 3） The effect of conservation tillage on improving proactive response was more pronounced in regions with higher levels of economic development and flatter terrain. Conclusion Conservation tillage can significantly improve the climate adaptability of grain production， mainly by strengthening proactive response， and exhibits evident path dependence and spatial spillover characteristics. The research findings provide a basis for optimizing agricultural climate adaptation policies from a dual-dimensional perspective and for enhancing the resilience of grain production systems.