Abstract: Based on the existing mine field boundary demarcated mode, there is a widespread technical economic problem, which it is difficult to stope coal under t he side slopes of two adjacent open pits when they excavate independently.To enhance the recovery rate of coal resources, reduce the cost of production, the authors p roposed the pivotal coordination mining technology of coal under side slopes in crossed limit area of two adjacent open pits includel stopes transfixing stopes and wast e dumps, building temporary transportation bridges between stope and waste dump, optimizing technical parameter and coordinately controlling engineering positions.T he results showed that by adopting joint coordinating mining technology, the two open pits not only stoped the coal under the side slopes in crossed limit area of two adj acent open pits reasonably and enhanced the recovery rate of coal resources, but also reduced the repetitive stripping effectively, uillized the dump space legitimately, r educed the waste dump land acquisition and short haul distances.In a word, the benefit is remarkable.