Installing HTseq is very straightforward for CentOS 6. You will need to do just follow the installation manual
# yum install python-devel numpy python-matplotlib
Download and untar the HTSeq source files.
# tar -zxvf HTSeq-0.5.4p5.tar.gz # cd HTSeq-0.5.4p5
Inside the expanded HTSeq home directories, to make HTSeq available for all users
# python setup.py build # python setup.py install
For more information, do look at