my husband holding z visa.we are indians.me and my child 1yr want to visit china for 1month.

My Indian colleague brought his family here in China for 3 months. So only for a month is no problem, you will get single entry permit. Please contact local Chinese embassy near to you, as documents required can vary a bit. No need to do medical check up. Have a look at vfschina.com, authorised to handle all the documentation for Chinese embassy in India, better to give them a call/email.
Source: I am from India, residing in PRC assisted my Indian colleague to bring his family here.