Visit family in china..

Hi,
my name is Yuemei Huang, I am a chinese citizen, also an Australian resident, I am married to a New Zealand citizen, we have two children born in Australia who are australian citizens. my children and I are booked to travel home to Guilin china leaving on the 23/4/15 and returning to sydney Australia on the 23/7/15. I hold a current chinese passport, our children hold australian passports, My husband wishes to apply for a visa to visit with us but traveling at a later date. Also he thinks he should apply for a multi visit type in case of emergency ..our plan is for him to come to china and to assist me with the children when we travel home and also for him to catch up with my family. do we need an invitation letter, or any other requirements.
regards Yuemei Huang