Abstract: Gangue gream-body filling is the main technological means of realizing green mine and the best technology to solve the problem of mine under water body，building and rail，and on karst water body and to control surface subsidence，which used the surface movement observation to evaluate the filling effect in the past，but cycle is often longer，cost is higher and amount of labour is larger using the mood of surface movement observation.To this point，developed the on-line monitoring system of paste backfill in the goaf，based on the KJ216 monitoring system of plank pressure.Comprehensively evaluated the filling effect through long-term monitoring of long-term stress，deformation and hydration degree of paste backfill in the goaf.The practice showed that the system worked well on site.

Key words: Gangue backfill paste, Backfill, On-line monitoring, Evaluation