Xu - how complicated is your python script? Are there many inputs and several output? An interesting solution from call python function from matlab (1) exists and it involves creating a python m-file (from the MATLAB perl.m, replacing the perl text with python. I tried it, along with their example, and it worked well. Basically it involves just creating a command string and evaluating it with the MATLAB dos or unix commands (depending upon your OS). Or, instead of creating the python.m file, you can just try with the same with a call to system. See call python function matlab (2) If your python script squares a number (like in the linked example) then you could simply write
commandStr = 'python /Users/myName/pathToScript/sqr.py 2';
[status, commandOut] = system(commandStr);
fprintf('squared result is %d\n',str2num(commandOut));
In the above, the path to the python script is explicitly defined. If the system call is successful, then status is zero, and we print out the result. Note that since the commandOut is a string, we have to convert it to a number.
For a simple example, this works very well. For a more complicated python script, it might be a little tricker.