Natural Gas hydrates (NGH), a new kind of environmentally clean energy, can stably exist at low temperatures and high pressure. To avoid the decomposition of NGH during exploration, the temperature and pressure at its original state must be properly maintained. Firstly, this paper presents the methods currently used in the NGH exploration, and then introduces the formula of low-temperature drilling fluids tested at laboratory by foreign countries that have rich experience in the aspect of NGH research. Continuingly, the rheological behaviors and the property of density of low-temperature drilling fluids are emphatically discussed. At the end of this paper, suggestions regarding NGH exploration are also put forward.