Im Vietnamese, working in Manila, i want to travel to Macau, can i apply visa in China emmbassy ?

Yes, you can apply from the embassy in Philippines. You should provide the following documents:
1. your passort (at least valid for six months and one blank page) and copy of your passport information page and emergency contact page.
2. Application form (you can download from the website of the embassy).
3. A photo. It should be recent, front view, white background, in 48mm x 33mm size without head covering.
4. Documents supporting your purpose of visit to Macau.