Welcome to SolidWorks forums Rongkorn.
A lower version of the software can't open up files from higher version. The only option is to save your files as a neutral format from SW2011 (which is not an option in student version, check this post: https://forum.solidworks.com/message/187815#187815) and then import/open those files in SW2010. But please note that you'll loss any history as model will come up as imported solid/surface body.
In case you're only looking to view them, use e-drawings. And if you looking to work further on what has been completed in school, best will to upgrade your home version to SW2011 or request your professor to have a SW2010 installed on one of the machine or your machine at school.
You might also find this post helpful for your future reference
Thanks so much, this is a drawback of SW2011 version. I just got SW2010 for 2 month and just installed it. If I've known a little bit early, I will buy a newer version.
This is not only with SolidWorks but almost every 3d software