I want family visit visa for 1 year or 6 months.

I am an Engineer and working in a Chinese construction company in China shandong province. I have my employment Z visa for 2 years by the company. I want to invite my family here in China for visit of 6 month or 1 year.
Plese tell me which documents, I need to prepare for this.
Any person or office which can help me about this or proceed my this case to get family visa.