How to use minicom to communicate with my BBB and my host?

I want to use UART2 pins to communicate with my host,and I use the FTDI FT232RL USB ship,but when I run minicom command ,it didnot show anything on my host screen.

The debug terminal is on UART0, so unless you are sending the data on UART2 yourself, then nothing will show up.

Assuming you are trying to send data on UART2, you need to make sure everything is set up correctly on your board. I have no idea which board you are using as you have neglected to say. In a couple of cases the FTDI cable will not work. In some case, the FTDI cable you use, if it is 5V will not work on nay board.

More information will help people answer your question.