For the windows platform, https://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv download the whl file corresponding to the python version and system version, and then pip install XXX.whl
There are two quick installation strategies on centos or ubantu. If there is conda, then directly conda install -c menpo opencv3, if not, you can try to download https://pypi.python.org/pypi/opencv-python/3.3.0.10 , opencv_python-3.3.0.10-cp35-cp35m-manylinux1_x86_64.whl, and then pip install it (I installed whl with pip successfully in ubantu, but not in centos, it is possible to use conda method in centos).