In an air relief valve structure of a pressure cooker, the pressure cooker includes a cooker body and a lid. The lid has a containing trough and an air relief valve. The air relief valve includes a middle column, an airtight column, an elastic element and a gravity valve. The middle column has a containing space and air relief and through holes formed on an outer wall of the middle column and interconnected with the containing space. In the containing space, an airtight column is installed. An end column is defined at an end of the airtight column and is disposed adjacent to an inner wall of the middle column, and the end column has a diameter equal to the diameter of the containing space of the middle column. The air relief hole allows food material to be discharged easily to reduce pressure and enhance the overall safety of the pressure cooker.