At first, I added the following line to /etc/fstab. Then I could mount it by a command “mount -a”.

However, it isn’t mounted on boot automatically.  I searched google, and it might be a problem is that the system tried to mount nfs before networking up. To avoid this, there is a mount option “_netdev”.

After adding the option though it still doesn’t mount on boot. In addition, I had to enable a systemd target named “systemd-networkd-wait-online.service”, otherwise the systemd still might try to mount the nfs before networking up.

Finally it turned to be mounted on boot correctly:D.

Solving NFS Mounts at Boot Time

https://wiki.archlinux.org/index.php/NFS#Automounting_shares_with_systemd-networkd