pwd取的是你现在的路径
比方你现在的路径是C:\Documents and Settings\AAA\My Documents\MATLAB
CSVDATA.directory = pwd;
=> CSVDATA.directory = 'C:\Documents and Settings\AAA\My Documents\MATLAB'
CSVDATA.directory = [CSVDATA.directory(1:2) '\CompDist\csvdata'];
=> CSVDATA.directory = 'C:\CompDist\csvdata'
CSVDATA.filename = 'year_sh2';
L = csvread([CSVDATA.directory '\' CSVDATA.filename '.csv'],CSVDATA.skiprows,CSVDATA.skipcols);
=> 读取路径是 'C:\CompDist\csvdata\year_sh2.csv'

X:\CompDist\csvdata

X是你Matlab Current Directory 所在的磁盘盘符

另外这种代码只能在Windows下面用，在Linux下用会出错。