China has three official tiers of cities, which roughly describes their level of development.
Tier 1 (Municipality) – These are big international cities; modern China. They are relatively safe and comfortable. You can get by using English and live as you did at home… well-educated people gravitate towards these cities, and the western influence is strong. They serve as a glimpse into China’s future, but may not give you a completely authentic “living in China” experience. Living costs in these cities are soaring. You’ll need a monthly salary of at least 8,000-10,000RMB to have a reasonable standard of living.
Tier 2 (Prefecture-level city) – Such cities are in a state of rapid development. A mixture of old and new, where you can still take a glimpse into China’s recent past. In these cities, you can get a taste of traditional Chinese culture whilst still seeing some western influence. Living costs are increasing but for the most part, still not that bad (unless you’re buying a house). You’d want a monthly salary of at least 5,000-6,000RMB to live comfortably.
Tier 3 (County-level city) – County-level cities are, for the most part, a window into China’s past. Step out of the city center, and you’re in rural China. You’ll get a powerful dose of traditional Chinese culture – not for the lighthearted! To live in one of these cities, an extremely positive attitude and passion for Chinese culture is an absolute necessity. Living costs are still relatively low in tier 3 cities. 3,000-4000RMB should be enough to live freely.
You can find a list of China’s cities, along with their population and city level on Wikipedia: http://en.wikipedia.org/wiki/List_of_cities_in_China_by_population