Hole bottom sampling freezing technology is an effective method to get gas hydrate cores, the cooling capacity of wire-line coring hole bottom freezing sampler is determined by the cold storage chamber which can store dry ice and cool down alcohol. In this paper, cold storage chambers with different internal structures were designed, the experimental studies were made on their cold storage capacity and cooling effect. The thickness of the insulation layer was calculated, and 3 types of internal structure for the cold storage chamber were designed. The tests of cold-keeping ability show that the average loss rate of dry ice is 31.3% after being stored for 1h, which can meet the requirements of subsequent alcohol cooling. The tests also show that the storage cold chamber with perforated-pipe can cool alcohol in a short time, and the cooling rate is up to 36.3℃, which can meet the requirements for gas hydrate freezing sampling.