I made an custom shader which had a displacement in it, when I was try to render out a image sequnence I found that the look of this material changes wildly which is not what I wanted, how can I make the displacement shader stop changing the look while rendering?

You are probably animating your camera or the object.
Make sure you do the displacement in object space.

Thanks Erik, yes indeed,I was animating the camera. As you suggest, I should do displacement in object space? But how to go about it? Is this the only way to fix this? Thank you!

Yes it is the only way and you should either use a Rest node in both SOP and SHOP or just a Transform node in SHOP depending on the situation.

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=102443&highlight=&sid=9663b54b4cb115c1674a33abd7922e3a [sidefx.com]
http://forums.odforce.net/index.php?/topic/12443-noise-displacement/ [forums.odforce.net]

One of these should contain how to do it but don't have the possibility to check it atm.

Thanks Erik, I tried, and It works! but there are still some tiny areas on the displacement surface that are not static, these tiny areas are flashing all the time! I don't know why.Thank you!