Their original paspsort, each one should fill one Visa Application Form, you can download the form from website or get it from Chinese embassy for free, one passport photo attached on the visa application form, two way flight tickets, invitation letter from you, copy of your resident visa and paspsort, Kinship certificate, such as birth certificate, marriage license, etc

Ms. Lorna, thanks a lot for the very helpful reply. And do I need to go to the thai embassy for the authentication of the letter of invitation? then i will mail it to thailand?then my family will present this authenticated letter for their visa application in my country?thanks again for your help regarding this. :)

The authentication of your Invitation letter in Thai Embassy is not required, but you'd better ask your company to send the Invitation Letter for your family with the stampt of your compny.