A memory system includes a first control circuit part configured to communicate with a host through a first host channel, a second control circuit part configured to communicate with the host through a second host channel, a first chip group configured to communicate with the first control circuit part through a first internal channel, and a second chip group configured to communicate with the second control circuit part through a second internal channel, wherein the first control circuit part and the second control circuit part alternately receive a plurality of data inputted through one of the first and second host channels, which is selected during a single channel operation, and transmit the data to the first chip group and the second chip group.