i have 10 hour lay over at Beijing, can i get out of the airport to have city tour?

Of course you can. Do apply for a stay permit at the immigration counter band you will be allowed to get out. I suggest you have a visit at Tiananmen Square and see the Forbidden City for outside (it only accepts online ticket booking now), then walk to nearby Qianmen for dining and shopping. If there is time left, go to Shichahai or Nanluoguxiang to tour around the Hutongs.