A compressor/decompressor (Codec) selecting apparatus includes a performance analyzer, a training server, a storage unit, and a selecting unit. The performance analyzer analyzes the performance of the current internet communication system, and outputs environmental parameters accordingly. The training server obtains learning data corresponding to a hyperplane according to training samples. The storage unit stores the learning data and the related parameters. The selecting unit does a functional analysis according to the environmental parameters and the learning data in order to select the Codec suitable for the current internet communication system.