运行startx命令显示如下：

gnome-session[19174]: devkit-power-gobject-WARNING: Couldn't connect to system bus: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory

gnome-session[19174]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory

gnome-session[19174]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory


解决方法：

经过一翻查找资料，发现跟图形模式默认启动的服务有关，用“chkconfig --list|grep 5:on”命令看看图形模式默认启动的服务，下面的服务改成自启动后我的就好了：
NetworkManager
abrt-ccpp
abrtd
acpid
atd
auditd
blk-availability
cpuspeed
crond
cups
haldaemon
irqbalance
kdump
lvm2-monitor
mdmonitor
messagebus
netfs
network
portreserve
postfix
rsyslog
spice-vdagentd
sshd
sysstat
udev-post
xinetd