Natural gas hydrate is formed under the specific conditions of low temperature and high pressure. Low temperature drilling fluid is the key to get high quality samples of natural gas hydrate during exploration work. Acceptable low temperature drilling fluid for natural gas hydrate should be characterized by low freezing point, good inhibitive capacity and flowability. According to the characteristics of natural gas hydrate exploration and based on the laboratory experiments, the comparison and analysis were made on the influence of molecular structure of PAM, PHPA, PAC-141, Na-CMC and KHm; type and number of functional group to the anti-collapse capacity and flowability of drilling fluids. The results indicated that the low temperature tolerance of above mentioned additives could be listed in order from low to high as PAC-141＜PHPA＜PAM＜Na-CMC＜KHm, which would provide important reference for the preparation and application of low temperature drilling fluid in natural gas hydrate exploration.