I have 6 hours for waiting at shanghai airport, can i go outside the air port or not ?

I'm Thai. I hold Thai passport. Now I'm working in Japan and hold the alien card of japan. I must waiting for transit at shanghai airport putong airport. I search from some WebBoard, they said if i just transit in PRC less than 24 hours. I can get out from the airport.

If i must apply one, Please introduce me.

Thank you.