Bus stations in China

Unlike flights and trains in China, bus tickets tend to have more availability, giving you the flexibility to change your itinerary at a moment’s notice. You don't need to bought a bus ticket earlier than a day in advance.  Chinese buses often run at a higher frequency than flights in China or trains. Most of the time you don’t have to worry about booking in advance because there will be a bus between two cities that runs at least once every hour, if not more. Compared to Chinese airports and train stations, security at a bus station is a breeze. You can arrive at a bus station any earlier than 30 minutes before my departure and you will still end up waiting for 15 minutes.
Most of the time, Chinese bus stations are located in the heart of a city as opposed to airports and train stations which are usually on the edge of town. This can not only save you time, it also saves you the expense of a taxi into town. 
Generally speaking, there are two basic kinds of buses in China: the seated bus and the sleeper bus. Sleeper buses also usually have A/C, an entertainment system and heating, although it all depends on the age of the bus you’re riding. Beds are priced higher for the top bunk than the bottom bunk in a sleeper bus.
With the exception of small towns, most cities in China have a number of different bus stations scattered around.

Often, bus stations are categorized by which direction their buses head (north, south, east or west). Others by which specific city or region they service.

You may to have an official form of ID (your passport) in order to purchase bus tickets. Once your ticket is bought, you can’t transfer this ticket to anybody else without returning it and buying a new one.