Dear gusarambula:
thanks for your quickly response.
we want to use the static ip address in the kernel,not u-boot.
I try to add the ifconfig eth1 192. ..... in the rc.local file and it works.
But I want to know why it does not work by the below method.
edit /etc/network/interfaces
auto eth1
iface eth1 inet static
address 192.168.0.12
netmask 255.255.255.0
gateway 192.168.0.1
in the BSP file(i.mx_linux_release_notes.pdf),there is a description about the kernel boot parameters below:

I set this in the uboot command line like this:
setenv ip=static_ip_address
But it still do not work in the kernel.
If you use the i.mx6ull-evk board to test,you can see it.
Furthermore,Could you tell me how to set the kernel boot parameters in the details?
Please give us support,thanks.
BRs
Tod