An international arrest warrant for the deposed Catalan leader and four of his former Cabinet members has been withdrawn.
Spain's Supreme Court says Carles Puigdemont and his team have shown willingness to return to Spain.
The five politicians travelled to Belgium after declaring independence for Catalonia following a referendum in October.
Mr Puigdemont and his four former colleagues face charges including embezzlement, rebellion and sedition, and face decades in prison.
The Spanish arrest warrant remains in place.
Despite Mr Puigdemont's position in Belgium, he addressed a political rally in Catalonia via video link for the official campaign launch.
He told supporters to view the election as the second part of the referendum.
He said: "The results of October 1st are still valid.
"There are many of us who don't give the Spanish government the authority to dissolve a legitimate legislature."