Polytetrafluoroethylene (PTFE) flat-sheet membrane with the mean pore size of 0.1m was used to treat the high concentration (NH4)2SO4 and NH4Cl solutions by vacuum membrane distillation (VMD). The permeate flux was varied in the range 8-48Lh-1m-2 and was dependent on the operating conditions. The effects of permeate pressures and feed parameters in terms of pH values, feed temperature, flow rate and feed concentration on both the permeate fluxes and the permeate concentrations of total nitrogen (TN) were investigated. Experiment results showed the feed temperature has the most significant effect on the permeate flux. The feed pH value was observed to be the most dominant factor on permeate concentration of TN. Ammonium was rejected with low feed pH value, high feed temperature and low permeate pressure. When the feed pH value was 3, the permeate concentration of TN was kept in the range of 1-3mg/L and the ammonia nitrogen rejection rate is 99.95%, despite that the feed concentration was increased.