The utility model provides a collection system for a rock core gas at a natural gas hydrate drilling scene. The collection system comprises a gas collection tank, a water bath incubator, a vibration table and a gas collection bottle, wherein the water bath incubator is placed on the vibration table, and the gas collection tank comprises a tank body and a tank body cover which are detachable and can be hermetically connected with each other. When the collection system is adopted for collecting the rock core gas, the tank body containing rock core samples is hermetically connected with the tank body cover in a constant-temperature water bath environment of the water bath incubator, and the gas collection bottle is connected with the gas collection outlet of the tank body cover in the constant-temperature water bath environment. The collection system provided by the utility model can be used for completing the whole process from encapsulation of hydrate rock core samples, gas release, gas collection, oscillation and gas collection to gas sealing and storage in one time, thus simplifying a series of intermediate process, and greatly improving the working efficiency of gas collection.