Multiple (two) undergraduate degrees in Phd application This year I will apply to graduate school in Statistic. My situation is:
I obtained first Undergraduate degree in computer science with very bad GPA (due to not focus on study). After that I worked as software engineer for one year.
Then I returned to another university and earn a bachelor degree in Math and statistic. This time I had very good record with highest GPA among math department and many research experiences. 

Now my question is: Do I need to include my first degree in CS in application or I just need to use my Math degree?
You need to follow the instructions on the application. 

However, most applications will want transcripts for all prior degrees. One good thing: you may not have been successful before but you were when you tried again. So, you've shown that you can be successful. That improvement is important to be able to demonstrate (as you've done).