The USBUART user module supports all standard baud rates possible on a serial port. In the physical sense, the Baud Rate does not apply to the USBUART as the data transmission in the USBUART takes place using the Full speed USB bus at 12Mbps. However, because of the virtual comm. port driver that sits between the PC and the USBUART (PSoC) device, the operating system will see the device as a normal serial port and will be able to set the baud rate.
Please refer application note AN2401 - Using the USBUART User Module for more information about the USBUART user module.