It's your income as her sponsor that matters more, though currently they do take into account applicant's overseas income, any combined savings and support from external sponsors such as your parents.
The minimum requirement is quite low, only £105.95 in cash per week after housing costs (rent/mortgage and council tax), though this is set to rise in near future.
It helps if your can submit her CV and any sample job vacancy she may be qualified to apply for, with salary offered, to show her job prospect in UK. Remember her teaching qualification won't be recognised in UK so she needs to look for opportunities away from state schools. She may be able to teach Chinese in language school or college?
In addition you can line up external sponsors as a safety net. If you don't have a place of your own, you may be able to share their homes rent-free?
You need to show evidence that your relationship is genuine, and that you will be committed to each other for life by having joint financial responsibility. While this is difficult to do while you are apart, you should set something set up like jt bank account and savings once she moves to UK.
To marry in UK, she needs to get a fiancée visa, and after getting married she applies for further leave to remain as your wife. If you get married in China (or elsewhere), she applies for spouse visa, which will be valid 27 months. In each case she will be eligible for settlement (indefinite leave to remain) after 2 years as your wife in UK.
