<p>Low level of comprehensive utilization technology for crop straw has constrained the development of agricultural carbon sink. The research on the preparation and application of biochar from straw for enhancing carbon sink function is of great significance for China’s CO₂ reduction. Through the analysis of the planting area distribution and annual straw output of major crops in China from 2017 to 2022, the potential of using straw to prepare biochar in China for enhancing carbon sink function was explored. The results showed that China’s waste crop straw resources were an annual output of more than 1.0 × 10⁹ tons, which showed an increasing trend. The development of biochar in China significantly reduced CO₂ emissions and obtained a big benefit of 3.5 × 10¹¹ yuan (RMB). China’s biochar industry has broad prospects, and the industrial needs included soil improvement, fuel utilization, by-product utilization, and CO₂ emission reduction needs. This study will help increase China’s CO₂ reduction.</p> Graphical Abstract <p></p>