Dissociated domain boundaries (DBs) attached to meta-dislocations have been found in a structurally complicated alloy phase (SCAP) of xi'-Al-Pd-Mn. On the basis of HREM observations and theoretical simulation, a structure model of DBs is proposed. The displacement vector R for the DB is determined to be 1/2 [1, 0, 1/tau] with a length of 12.37 angstrom.