1. check where the file resides:

find /usr -name libpython2.5.so.1

This shared object seems to be in a different directory than expected by your program. Maybe it helps to create a symlink to /usr/local/lib like
sudo ln -s /path/to/libpython2.5.so.1 /usr/local/lib/libpython2.5.so

I've tried but I can't find the file libpython2.5.so.1

my situation as follows:
/usr/local/bin has cmd python and python2.5
/usr/local/lib/python.2.5 has the python's py and pyo files

So my python2.5 lib lies in /usr/local/lib/python2.5 ,but it seems the system couldn't find it through env variable LIBPATH.

any help would bu appreciated.
Thanks.

Please have a look here:
http://m5.eecs.umich.edu/wiki/index....n_installation
(Using a non-default Python installation)
'libpython2.5.so.1': if you build python yourself, this option should be used to
get the shared library: '--enable-shared'

Is there any reason you installed python manually? In many cases, it is a lot easier to install it from a repository.

I have checked that the Python 2.5 is installed as /usr/bin/python2.5
and the Python2.5 library is in "/usr/local/lib" rather than "/usr/lib"

I have done these:
[Python2.5 path]$configure --enable-shared
[Python2.5 path]$make clean
[Python2.5 path]$make
[Python2.5 path]$make install

but is still says can't find Python library python2.5

The passage also says:
" typically by adding the directory to your LD_LIBRARY_PATH environment variable"
it means that add "/usr/local/lib" to LD_LIBRARY_PATH ?
How to find the env var LD_LIBRARY_PATH and modify it?

Thank you!

I guess it's a good idea to have all python in one 'prefix'
So try instead: make clean, and move away these files:
Makefile, config.log, config.status (if there) and then:
./configure --enable-shared --prefix=/usr

(Concerning LD_LIBRARY_PATH I used to add a line to /etc/ld.so.conf :
/usr/local/lib )