确认刚刚安装的内核的位置,然后将default修改一下

 # Note that you do not have to rerun grub after making changes to this file
 # NOTICE:  You have a /boot partition.  This means that
 #          all kernel and initrd paths are relative to /boot/, eg.
 #          root (hd0,0)
 #          kernel /vmlinuz-version ro root=/dev/mapper/vg_have-lv_root
 #          initrd /initrd-[generic-]version.img
 #boot=/dev/xvda
 default=0
 timeout=5
 splashimage=(hd0,0)/grub/splash.xpm.gz
 hiddenmenu
 title CentOS (3.10.63-1.el6.elrepo.x86_64)
    root (hd0,0)
    kernel /vmlinuz-3.10.63-1.el6.elrepo.x86_64 ro root=/dev/mapper/vg_have-lv_root rd_LVM_LV=vg_have/lv_root rd_LVM_LV=vg_have/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us console=hvc0 crashkernel=auto rhgb quiet
    initrd /initramfs-3.10.63-1.el6.elrepo.x86_64.img
title CentOS (2.6.32-504.3.3.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-504.3.3.el6.x86_64 ro root=/dev/mapper/vg_have-lv_root rd_LVM_LV=vg_have/lv_root rd_LVM_LV=vg_have/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us console=hvc0 crashkernel=auto rhgb quiet
    initrd /initramfs-2.6.32-504.3.3.el6.x86_64.img
title CentOS (2.6.32-358.6.1.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-358.6.1.el6.x86_64 ro root=/dev/mapper/vg_have-lv_root rd_LVM_LV=vg_have/lv_root rd_LVM_LV=vg_have/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us console=hvc0 crashkernel=auto rhgb quiet
    initrd /initramfs-2.6.32-358.6.1.el6.x86_64.img
title CentOS (2.6.32-220.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-220.el6.x86_64 ro root=/dev/mapper/vg_have-lv_root rd_LVM_LV=vg_have/lv_root rd_LVM_LV=vg_have/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us console=hvc0 crashkernel=auto rhgb quiet
    initrd /initramfs-2.6.32-220.el6.x86_64.img
title CentOS (2.6.32-131.0.15.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-131.0.15.el6.x86_64 ro root=/dev/mapper/vg_have-lv_root rd_LVM_LV=vg_have/lv_root rd_LVM_LV=vg_have/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us console=hvc0 crashkernel=auto rhgb quiet
    initrd /initramfs-2.6.32-131.0.15.el6.x86_64.img

新装的内核位置为0,所以将default修改为0,保存退出重启