I'm Indonesian who is currently in Japan on holiday. Need visa to China , can I do it in Tokyo?

You need to apply the L visa through a travel agency, otherwise the embassy/consulate would refuse your application.

The documents are as following:
1. A valid passport with enough blank pages and 6 months validity; copy of the imformation page;
2. One recently taken, bareheaded, full-faced photo;
3. A Chinese hotel reservation certificate and a two-way air ticket;OR invitation letter
4. Visa application form (V2011A and V2011B);
5. Former Japanese visa

Rush service is available with ¥3000 for next-day pick up.

Good luck!