Abstract: One of the underground gold mines in Hebei province，ore mixed with 5% cement filling body when mined，result in some problems such as Floatability decline of nature gold and pyrite associated gold，flotation foam becoming small and sticky，grinding fineness artificially high on the native gold and gold content pyrite，which seriously affects the gold recovery and the stability of the production process.In order to solve the problems taken by cement filling body，the structure of process and pharmaceutical system was improved and optimized，and the condition of Nelson concentrator are modified on the basis of laboratory test and industrial test.The Nelson gold concentrate grade and recovery reached 1 656.37 g/t，21.79% respectively after modification，and the flotation gold concentrate grade and recovery reached 107.61 g/t and 70.03%，and the gold concentrate recovery of nelson and the all flow raised 4.42 and 6.47 percentage points respectively.For the problems exposed by the scene，measures from the tests are feasible and effective，and can provide reference for the similar mines.

Key words: Cement filling body, Defoamer EDA, CuSO4, Nelson concentrator, Flotation