Abstract: Nepal has complex geological conditions, low degree of hydrocarbon exploration and investment, and low degree of understanding about the petroleum geology.But there are abundant surface and borings shows of hydrocarbon in Lesser Himalaya and its south.In order to understand the hydrocarbon potential of the mountain front in Nepal, the authors intend to combine the previous and the new research results to summarize and analyze the petroleum geological characteristics in the Lesser Himalaya of Nepal and its south.The results show that there are many large scale potential layers as source rocks in Lesser Himalaya of Nepal and its south, and there are also a assemblages formed by potential source rocks, reservoirs and cap rocks.Neotectonic movement is the key to control the regional migration and the adjustment of hydrocarbon.Both of the abundant hydrocarbon shows and the static petroleum geological conditions indicate that Nepal's Lesser Himalaya and the south, especially south of MBT, have good prospects for hydrocarbon exploration.