There are provided a memory system and an operating method of the memory system. The memory system includes: a main controller for transmitting main data having N bits through a main channel, where N is a positive integer; memory devices for storing sub-data constituting the main data, and transmitting the sub-data through sub-channels; and a sub-controller for communicating with the main controller through the main channel, and communicating with the memory devices through the sub-channels. The sub-controller generates the sub-data each having n bits where n is a positive integer less than N, by dividing the main data, generates sub-data strobe clocks by decreasing a frequency of a main data strobe clock synchronized with the main data, and transmits/receives the sub-data to/from the memory devices in synchronization with the sub-data strobe clocks.