Abstract: A flexible tool case accessories compartment assembly structure wherein the compartments in the tool case for collection of a variety of accessories are flexibly arranged according to requirement. It is to integrally made an inner receiving space inside a tool case on either corner with the inner side wall of the receiving space integrally made to provide a plurality of vertical grooves arranged at equal interval to match with a variety of stake racks which are also integrally made to provide a plurality of vertical grooves arranged at equal interval, such that the receiving space may be flexibly divided into a variety of compartments in specific sizes to fit for specific requirements. A plurality of stop logs are made on the top of the receiving space around the periphery to define an opening at one side and to define a sliding way therebelow so as to let a cover board be set therein to cover the receiving space.