With the sustainable development of deep volcanic rock and conglomerate gas reservoir in Daqing oilfield, there is an urgent request of developing deep gas reservoir with horizontal well technique. The paper described the geological characteristics of deep volcanic rock and conglomerate and the features and difficulties of horizontal well in volcanic rock and conglomerate. Research was made on bit selection, well trajectory optimization, well structure optimization, BHA selection and the under balanced drilling pressure value control with several field test wells completed. The average penetration rate is 2.79m/h in Xushen-P34 well, and a series of horizontal well drilling techniques has been developed for exploration and exploitation of the deep volcanic rock and conglomerate gas reservoir in Daqing oilfield.