I entered the U.S as B1 on 2010 for 3 times, which counted less than 180 days in total. And I will go to the U.S as L-1B on March 2011. Should I fill the tax return form for year 2010?

If you did not earn any income while in US, you do not file 2010 tax return. http://taxipay.blogspot.com/2008/08/us-visas.html

Thank you for your reply!
I did not have income paid by us company. I was paid by their China branch. So I don't need to fill that form. Right?

What is your citizenship? Answer will be based on tax treaty between your country and US.