What is the limit of baby formula milk I can bring into beijing?

My husband is working permanently in beijing. I would like to bring my 6mths old infant to stay over there and bringing in baby formula milk into beijing. What's the limit number of tin I can bring in (limit of size of per tin and per pax?). My husband traveling with me, so each of us can bring that number of tin even only with an infant? Do I need to declare even I do not carry more than the limit that can bring into beijing?