The Earth is primarily the same as the real Earth, however it does not share the same real information such as countries and places. The technology seen in the series seems to be a mix of current and future technology, such as the "Capsules" invented by Capsule Corp, which look like small pressurised tubes which fit in your palm, but can contain entire houses, for example. The animal population is also slightly different, mainly because dinosaurs are not extinct and freely roam the countryside. The marine life also contains prehistoric elements. Certain animals are highly intelligent, and are often seen mingling with humans, as if they are just another person in the greater population. Some of the main characters are such animals, Oolong is a pig, and Puar is a cat. There is also a talking turtle on Kame Island.
All planets have a Guardian in Dragon Ball, who watches over the planet. Earth thus has one. Throughout most of Dragon Ball Z, the Earth's guardian is Kami, and then later Dende after Kami had fused with Piccolo. Because Kami and Dende are Namekianss they have the ability to create Dragonballs, which have the ability to grant wishes if they are collected. These wishes are used regularly throughout Dragon Ball for many various things, such as bringing people back to life, or wishing for the worlds most comfortable pair of underpants.
The locations depicted in Dragon Ball are obviously heavily influenced by Asian cities, and a lot of their customs are seen in the series. An example of this can be seen in the scenes with any food involved, as they include oriental influences such as the style of food, and even chop sticks are used for eating with. The cars seen in Dragon Ball often float rather than having wheels, suggesting a technologically advanced society.
At one point the Earth is blown up by Kid Buu, but it is wished back by the new Namekian Dragonballs.