The mechanism of small premium catastrophe insurance is not only an important part of the catastrophe risk management mechanism, but also an important source of funds for prevention and mitigation of disasters and for disaster recovery and reconstruction. It is of great significance to ensure the sustainable development of social economy. The catastrophe risk is insurable, under the condition of perfecting the catastrophe insurance law systems and in accordance with the government as the leading factor, and in combination with the market model, establishment and spreading of the scientific and reasonable mechanism of catastrophe risk, broadening catastrophe risk fund accumulation channels, and achieving universal participation in the micro catastrophe insurance. The small premium mechanism of catastrophe insurance in Hunan Province has been established in this paper based on five main bodies, i.e. the policy-holder, the direct insurance companies, the reinsurance companies, the capital market, and the government, according to the theory of micro insurance and practical experiences in Hunan Province. It also puts forward the policy suggestions on promoting the construction of small catastrophe insurance system in Hunan as soon as possible. Results have provided good decision-making bases for all the sectors of the Hunan provincial government.