First, if you apply for a visa, you can go to the Philippine Embassy in China for certification with your single certificate.
Second, you can register your marriage at the local foreign-related marriage registration office.
Third, get a marriage certificate and apply for an extension at the local public security passport office. At first, you can sign it every three months. If you can use some contacts to countersign for a long time, don't forget that your girlfriend will get a temporary residence permit at the police station where your household registration book is located more than 24 hours after registration.