Double transit china within 24hours

It doesn't matter whether you leave the airport or not, because CAN-PEK is a domestic flight. As is the norm of almost all countries in the world (and the Schengen area), anyone boarding a domestic flight after arriving from an international flight has to go through customs and immigration at the point of entry (Guangzhou in your case). The problem is that if you attempt to pass through immigration you will be deported back to where you came from because Guangzhou immigration will not let you in the country when traveling like this. The only way to travel is to change your flight or get a transit visa. Got it?