1. If you have valid Korea visa, you can apply for Chinese visa in South Korea, however, sometimes, the visa officers will ask your to provide Korean work permit or residence permit instead of Korean visa. Korean work permit or residence permit can prove that you can stay in S.Korea for a long time, the short visitors to S.Korea holding short-term Korea visa can't apply for Chinese visa in S.Korea, you can have a try!

2. The requirements for business visa are:
an original notice of visa authorization from a duly authorized Chinese organization in China

Application form: All applicants should fill in one visa application form appropriately and authentically

One recent passport size photograph.

Applicant's passport valid for at least six months with at least 2 blank visa pages; the copy of your passport's date pages

hotel reservation, two-way flight tickets.

3. it takes 4 working days normally, you have to apply for Chinese visa through the authorized travel agencies.