Abstract: In order to prevent roof accidents and support pushed down at fully mechanized caving face with large dip angle in mining process, the methods of combining numerical simulation with mine pressure monitoring are used to study strata behavior at 1604 fully mechanized caving face, the peak of abutment stress is 8.1 MPa, which is away from the working face of 12.2 m; stress influence range is 4.7 to 31.8 m; the stress concentration coefficient is 1.81. The range of first collapse step for immediate roof and basic roof is determined. The basic roof periodic weighting step of face is 11.8 m; dynamic load coefficient is 1.58; maximum working resistance of working face during weighing period is 4 278.8 kN, which is the rated working resistance of 62.9% ; support has enough surplus capacity with better reliability.