A communication device of handling a network feature comprises a storage unit for storing instructions and a processing circuit coupled to the storage unit. The processing circuit is configured to execute the instructions stored in the storage unit. The instructions comprise receiving system information indicating whether an Evolved Packet System (EPS) optimization is supported and a first Non Access Stratum (NAS) message indicating whether the EPS optimization is supported; determining to use the EPS optimization, when the system information indicates that the EPS optimization is not supported and the first NAS message indicates that the EPS optimization is supported; and determining not to use the EPS optimization, when the system information indicates that the EPS optimization is supported and the first NAS message indicates that the EPS optimization is not supported.