I'm using NHibernate version: 1.0.4

Can i disabled 2nd level cache without modify the class mapping ?

thanks,

Yes, all you would need to do is to remove the sections that deal with 2nd level cache from the web.config:

<add key="hibernate.cache.use_query_cache" value="true"/>
<add key="hibernate.cache.provider_class" value="XXXX" />

You can even leave the <cache usage="XXXX" /> in your mapping files, in case you do not want to use 2nd level cache for now. This will make it easier for your to turn on 2nd level cache later if you decided to use it.