To protect the adit pass and slope,the mass of engineering and technical personnel in Lanjian Iron Mine have explored the in-hole and between-holes microsecond blasting technology.To determine rational microsecond delay time is both the requirement of ensuring blasting quality and the key to achieve blasting vibration reduction.The paper describes the determination of in-hole and between-holes microsecond delay time,the detonation mode and the network connection and their application effect.