Data transmission method and system, controller and storage medium

The invention relates to a data transmission method and system, a controller and a storage medium, and the method comprises the steps: obtaining a data size and an address form corresponding to a write command under the condition of receiving the to-be-processed write command, and carrying out the data transmission according to a transmittable data size corresponding to a flash memory channel for data transmission; and splitting the write command according to the data size corresponding to the write command to obtain at least one sub-command executed in sequence, wherein each sub-command has a corresponding sub-data size and corresponding sub-address information. The channel state of at least one flash memory channel is polled, and under the condition that the channel state of the flash memory channel is idle, subcommands are distributed to the flash memory channel. And obtaining the logic data block according to the sub-address information corresponding to the sub-command, and writing the logic data block in