When Linux encounters multiple NICs

My virtual machine has three network cards, there are two in use, respectively, is a different network segment

1. Eth4:192.168.100.6/24
2. Eth6:192.168.137.131/24

But the default system sets my internal network eth6 to the place where all IP addresses need to go, as follows

~ $ip Route
192.168.100.0/24 Dev eth4 proto kernel scope link src 192.168.100.6
192.168.137.0/24 Dev eth6 proto kernel scope link src 192.168.137.131
169.254.0.0/16 Dev Eth4 scope link metric 1002
169.254.0.0/16 Dev eth6 scope link metric 1003
Default via 192.168.137.1 Dev Eth6

So execute the following command as Root

IP route del default
IP route add default via 192.168.100.1
Delete the default gateway interface Eth6, add the defaults to the Eth4 gateway, where default is the/etc/networks file from CentOS, and the default alias is 0.0.0.0