Abstract: In order to improve the fracturing effect and increase the productivity, the adaptability of the fracturing fluid systems applied in field was comparatively analyzed. The foam fracture system was selected in consideration of the characteristics of low filtering loss, strong sand carrying capacity, low damage and auxiliary flowback which is suitable for the fracturing of high stress deep coal seam. On this basis, nitrogen foam fracturing field application test were carried out in two wells. The results showed that construction pressure of nitrogen foam fracturing is stable, sand ratio is increased, sand adding is continuous, and the average increase of single well gas production had exceeded 1 000 m³/d.