Beijing - Guangzhou Train vs. Plane

A high speed train ride takes 7.5-11 hours from Beijing to Guangzhou, while flight may take 3.5 hours. If you are traveling in a hurry, flight is better. If you want to enjoy the great scenery changes between northern and southern China, high speed train is a good choice as well.
 

Trains		Flights
Daytime Bullets	Overnight Bullets
Second class seat: CNY862	Sleeper: CNY1,150	Usually CNY500-2,000
7.5-10 hours	10-11 hours	3.5 hours
Punctual	Punctual	Frequent delays
Good; Wide legroom	Good; Sleepers to lie down	Good; Narrower leg room
6 per day	3-6 per day	50+ per day

 See detailed Beijing - Guangzhou High Speed Train
 Although passengers are able to enjoy great discounts for a flight in most cases; it still costs around CNY 500 to 2,000. In comparison, on high speed trains a second class seat costs CNY861.5-964.5. For budget travelers, railway may be more preferable most of the year. But sometimes in low seasons, air ticket can be quite tempting. 
 Even if both airports are located far away from the downtown area, the total air trip takes less time than a rail ride counting the transfer time to and from the airport or railway station. The total time needed by train is 9.5-13 hours, while the total time by air is about 7.5 hours.

High Speed Train	Flight
0.5h between Beijing West Railway Station and downtown	1h between downtown Beijing and Capital Airport
1h for boarding and 7.5-11h onboard	2h for boarding and 3.5h on plane
40min between downtown Guangzhou and South Railway Station	1h between Baiyun Airport and downtown Guangzhou
It takes about 9.5-13h in total.	It takes at least 7.5h.

 Generally speaking, train is more punctual than flight because of its fixed schedule, and they cannot be easily affected by weather change, air traffic control or other external factors, while flight delays often happen.

First Class Seats in a High Speed Train

Sleepers in an Overnight High Speed Carriage

They shuttle between the two cities from Friday to the next Monday overnight from late evening to early next morning. As they are equipped with sleepers, you are able to have a good rest onboard and rejuvenate yourself. Obviously, it can also save you one-night accommodation expenditure, and the daytime for those who are pressed for time.
 When you travel by aircraft, mobile phones should be switched to flight mode and cellular data are forbidden to use; you cannot move around casually; and the legroom is limited. However when traveling by rail, you can use your mobile devices to surf the internet, the legroom is much wider and you can move around and have a stretch.
 There are over 50 flights between the two cities each day, while about 12 pairs of bullet trains operate with fixed schedules. When you take a flight, there are more choices for your convenience.
 The very long Beijing to Guangzhou high speed railway runs from the capital city to the excellent port on the Pearl River passing by several provincial capitals such as Shijiazhuang, Zhengzhou, Wuhan, and Changsha. When you travel by high speed trains during the day, the scenery along the way varies; you can appreciate historical sites, the famous Yellow River and Yangtze River, the beautiful lakes and mountains as well as fertile rural areas, and finally arrive in a city with tall buildings, bustling streets and other popular tourist destinations. In comparison, flying will be less interesting because you can enjoy nothing except the blue sky and a bird's eye view of the cities.

It is all a matter of personal preference as to which one to choose. If you are a budget traveler, the overnight sleeper trains are the best; the normal type is cheaper but not recommended for the old facilities and poor environment. If you are pressed for time, a flight should be the top choice regardless of delays. If you travel in high season or want to enjoy different scenery in a short time, the daytime G trains are recommended.

 Also read: How to Travel from Beijing to Guangzhou