Abstract: Jinchanghe Polymetallic Mine has gradually entered the two-step pillar stope mining stage. In view of the complex boundary problems formed by the one-step stope，the roof collapse investigation and filling body quality evaluation of 21# and 23# stopes are carried out. With the help of GEOSLAM mobile three-dimensional laser scanner，the goafs on both sides of the two-step pillar stope are detected，and the boundary range of the 22# pillar stope is accurately obtained. By dividing the two-step pillar stope into three ore sections，and implementing the basic principles of weak mining，strong output and strong filling under the system of shrinkage blasting during blasting mining，the reasonable caving method，blast hole layout and hole network parameters，initiation mode and charging structure of 22# pillar stope are determined. The field construction shows that the blasting effect of 22# pillar stope is good and the filling bodies on both sides are stable，which greatly improves the safety of pillar stope. It can provide reference for blasting mining de⁃ sign of pillar stope with complex boundary in similar mines.

Key words: complex boundary, pillar mining, blasting technology, backfill quality