Abstract: In view of mary difficulties in underground construction，put forward the proposal of dynamic monitoring in the process from open-pit to underground mining，rational arrangement and monitoring in the number and degree should be adopted to related techniques，working category and procedures.The underground construction was greatly improved by applying united exploiting and transporting system,as well as bidirectional digging scheme and layout; ensured the safety of open-pit side slope by grading the stability of high and steep side slopes and sectioning and reinforcing the anchor cable and net; separated open-pit from underground production by applying the extension method without expanding side slope and allocating in-phase separated pillars; ensured highly efficient production from open-pit to underground by conducting multi-location and multi-method operation; improved the safety for Large waterflow mine from open-pit to underground by carrying out various precautious and draining measures.With the further study of dynamic monitoring technology in the safe and efficient mining from open-pit to underground，as well as the rational and orderly construction organization，Guilaizhuang Open-pit Mine witnessed a successful transition from open-pit to underground mining without any decreasing output.Meanwhile，the safe and efficient exploitation may be ensured in this case.

Key words: Open-pit to underground, High and steep side slope, Large waterflow mine, Safe and efficient production, Dynamic monitoring