Since the late 1980s, the Tibetan Plateau has continued to warm, and this trend is higher than in other parts of China. Some studies based on remote sensing data and planting suitability models showed that sufficient agricultural heat resources in the region increased the area suitable for cultivated land and created favorable conditions for farming and herdsmen's reclamation. However, there has been a lack of empirical research on whether and why farmers and herdsmen reclaim these lands and how they balance the opportunities, risks, and population pressures brought by climate change. In this paper, three typical grain producing regions of the Tibetan Plateau (the YNL river region, He Huang Valley, and Zamtang county) were chosen as the research areas, and 605 households' survey data were used to analyze the influencing factors for farmers' and herdsmen's reclamation behavior. The results showed that there was a significant positive correlation between farmers' perception of winter duration, total household population, dependency ratio and farmers' reclamation behavior; there was a significant positive correlation between farmers' perception of precipitation, annual wage per capita, education level of household heads, whether to borrow or not, and the distance from residence to town and farmers' reclamation behavior. With the acceleration of urbanization, the recognition of farmers and herdsmen towards non-agricultural work is increasing. With the government's control, reclamation is not widespread. Because reclamation is likely to cause irreversible negative impacts on the ecological environment of the Tibetan Plateau, we should provide more non-agricultural employment opportunities, promote agricultural intensification, and strengthen supervision, to reduce the possibility of reclamation.