if i want to integrate realsense into my product and go to mass production,how can i buy the realsense module,other than the dev kits?
Whilst Intel encourage manufacturers to incorporate the cameras into their products, the details for how to go about doing this or who to contact to inquire about it do not seem to be public knowledge at the moment. This link to a forum post about someone else who asked about it may be of interest to you.
Edit: I'm reminded of one of entrepreneur Peter Diamandis' laws of success in business - go to the top for answers. So why not send an email to the Intel CEO. If you don't ask, you don't get! :)