I upload a ms word document ,and I can find it in le file system (GUID.BIN),and i open it ,change it ,then close it ,but i get the doc from web is not i want .some can tell me why ?
You should never directly access the .bin files in the alf_data subfolder, as this undermines the data integrity of the content management system. This is true for all content management systems, not just Alfresco! In a "real life" system you should prevent users from directly accessing the alf_data folder at all.
If you want direct file access to the content, you should use the CIFS interface.