Abstract: Xincheng Gold Mine employ the shaft and auxiliary ramp development mode，and mechanized panel upward backfill mining.At present，the scale of production reaches 6 000 t/d.Many problems exit in the deep-well backfill mining of Xincheng Gold Mine ，including long backfilling pipeline，partial filling times line up to 12.5，many pipeline quarter turns，serious pipe wear out，difficult guardianship，pipe blockage and mortar leakage in the backfilling process.Through the study of the relationship of filling times line，backfilling density and backfilling flux of Xincheng Gold Mine，we optimize the backfilling line；backfilling pipeline performance was studied comparatively and the backfilling pipe was choosed reasonably to reduce the pipeline impedance；through experimental research，Minefill309 was added in storehouse，and a new chemical reagent Minefill501 was added in vice bucket to improve mortar flow characteristics，which could prevent slurry segregation，reduce pipeline abrasion， increase service life of pipeline more than doubled，and achieve considerable economic benefit.The filling concentration is stable between 75%～78%.The technology fills in the blank of theory and practice of the high-density gravity-flow backfilling，which can provide promotion and guidance for the industries at home and abroad.

Key words: Deep-well, Long distance, Large times line, High density, Gravity-flow backfilling technology