Abstract: The conventional string for 3-layer fracturing and commingled production in gas well in Sulige gas field represents imperfectness like the packer can not be set effectively after ball dropping and ball seat shear-out, secondary setting can not be realized, the ball staying in the string after fracturing restricts the displacement and gas recovery, and the string is difficult to pick up due to many anchors on it in later fracturing. In view of the above problems, the new unhindered frac-string for 3-layer fracturing and commingled production in gas well has been developed. This string employs BZ-K344 packer with unhindered sand-blast sliding sleeve and it is designed with long tubing, ensuring favorable sealing effect by means of repeated setting during construction; the lower big-bore packer and the lower hydraulic anchor make all the sliding sleeve cores reach the downhole successfully, thus realizing the smooth production of full well bore. A total of 35 wells have been drilled with desirable effect in Sulige area from 2011 to now.