Does Certificate of Kinship should be authenticated?

You are supposed to get the certificate authenticated, I suppose. If you doubt that, you can call the China embassy to confirm that.
To authenticate the certificate, you should first get it notarized by the local notary public and the regional trail court and Ministry of Foreign Affairs of your country); and then go to the embassy of China to get that attested; the required documents include your passport and its copy, the application form for attestation, and your certificate and the copy.