The high-water solidifying material is a kind of special concrete. Its main properties are introduced such as strong water-solidifying capability, fine pumpability and pumpable for a long time, quick setting and with early-developed strength, high residual strength after being cracked, etc. This material has been used with satisfactory results in entry-side packing to maintain an entry along the gob edge. The deformation mechanism and relevant parameters of the entry-side packing body are analyzed. A technique of "three-dimension reinforcing net with bolt for entry-side packing" is emphatically introduced to control the stability of the packing body, and the good reinforcing effects of the packing body are also shown by the field measurement results. The high-water material and the reinforcing technique lay a good foundation for the successful test of gob-side entry retaining in fully-mechanized coalface with top-coal caving.