In this paper, the landfill gas generation process was investigated by a landfill lysimeter of municipal solid waste (MSW) co-disposed with wastewater sludge. The experimental results show that the wastewater sludge played a role of inoculation in MSW degradation process and accelerated organic waste decomposition. Compared with the MSW landfill alone, the landfill gas generation rate of MSW co-disposed with sludge was higher by about 30%. The average CH 4 content in landfill gas reached 64%, which was much higher than in case of MSW landfill alone and useful for landfill gas utilization. It is also proved that co-disposal of sludge with MSW is a good choice for beneficial use of sludge.