For a U.S. citizen who is travelling in Europe and wants to fly from Europe to China, what is the recommended way to obtain a Chinese visa?
The Chinese Emabassy in the UK site refers visa applications to the Chinese Visa Application Service Center. According to this site, they have locations in London, Manchester, Stockholm, Gothenburg, Copenhagen, The Hague, Brussels, Paris, Marseilles, Milan, Rome and Madrid.
The terms of their online application state that applicants must be a citizen or resident of the country where the application is made.
However, you may be able to make an application in person at one of these locations or at a Chinese embassy or consulate in Europe. As others have reported success doing this.
You can also send it back to an agent in the US, such as US-China Chamber of Commerce to do the visa as long as your passport shows that you are not inside China, i.e., exit stamps.
Using a reliable agent will eliminate a lot of uncertainties, and you do not need to take days off. Also, in theory, you are supposed to get the visa from a Consulate in the country which you come from though US citizens do get visas outside the US. However, you need to take the shipping cost into consideration.
This could cost between US$60 and US$100.