It is the premise for the diesel generator set to maintain the proper indoor environment of underground diesel generator plant. Based on the analysis and summarization of the merits and drawbacks for the diesel generator set heat exchange modes and ventilation and cooling schemes of underground diesel generator plant, this paper proposes a novel ventilation and cooling scheme for water cooling and wind cooling diesel generator set, separately. Finite volume method software is adopted to do the numerical simulation. The results show that the novel scheme, which can carry out the heat and contaminants simultaneously and effectively, may overcome the disadvantage of the ventilation and cooling schemes before.