There are no direct flights from Beirut to Guangzhou. However, flights with transfers at Dubai, Kuala Lumpur, Doha or Paris are available daily. And among them, there are flights provided by Emirates Airlines, Malaysia Airlines, China Southern Airlines and so on.

Transferring at Dubai will cost less flight time. Here is the flight schedule for your reference:
Beirut – Dubai, EK956, 0355/0810, Emirates Airlines,
Dubai – Guangzhou, EK362, 1035/2220, Emirates Airlines

For more, you can consult some booking agencies or the airlines directly.