Abstract: This paper studies systematically the effects of wellbore diameter, wellbore trace, horizontal section length and eccentricity on production of horizontal well. The further research on the effects of heterogeneity of oil reservoir, position of horizontal well for different drive manner, formation damage caused by drilling fluid, different well completion technologies and stimulation on production of horizontal well. This paper also derives the calculating equation of maximum length of horizontal section, presents the reasonable selection of controllable parameters, and points out the ways enhancing oil production of horizontal well.