As a potential huge energy reservoir,natural gas hydrate has a significant impact on climate and marine environment due to its decomposition and release of methane. However,the influence of gas hydrates on environment and biological community has not been thoroughly known. There are a huge amount of methane reservoirs in the seafloor and permafrost in Svalbard and its adjacent areas in Arctic,which is very sensitive to the climate changes,well known as one of the best natural laboratories to study climatic,environmental and biological effects of the gas hydrate decomposition. This paper systematically summarized the relationship between the hydrate decomposition process in Svalbard and its adjacent areas and its effects on climate,marine environment and biology. The results are shown as follows: (1) The current annual emissions of CH4 linked to the decomposition of gas hydrates in the study area cannot reach a level which is detectable against the background emissions,so the effects of CH4 on climate might be limited; (2) Gas hydrate dissociation is often considered as a precursor or triggering factor for submarine slope failures,but not a main cause; (3) The emissions of CH_4 can break existing chemical equilibrium,the distributions and transfer pathways of productivity,biological coupling, the connectivity among habitats and the final benthic community. These results might provide references for studying the possible impacts of natural gas hydrate exploration and production on ecological environment and its prevention and control measures.