FARI (Flexible Architecture of Reconfigurable Infrastructure) is proposed for a future information and communication infrastructure network. This architecture is dynamic and flexible, and can meet various requirements of future networks. Based on the atomic capability theory of FARI and the traditional I/O matching algorithm, an atomic capability chain composition method is proposed. This method can combine a series of atomic capabilities to an atomic capability chain, according to special business requirement. And it can automatically compose some ACs with independent function characteristics into a chain which satisfies the business requirement. Traditional I/O matching algorithm just specifies the matching between input and output parameters. Our improved I/O matching algorithm specifies not only the matching of I/O parameters, but also the matching of metadata which is specific to ACs. At last, an example is provided to illustrate how this method works, and a simulation is given to show the efficiency of this method.