For the first time, DySrAlO 4 of K 2 NiF 4-type structure was synthesized. The parameters of DySrAlO 4 elementary unit cell are determined as follows: a = 0.368 (4) nm, c = 1.229 (2) nm, V = 0.166 (4) nm 3. The research of the complex aluminates LnSrAlO 4 (Ln = Nd, Gd, Dy) solid-state process demonstrated the change of the formation mechanism among LnSrAlO 4 (Ln = Nd, Gd, Dy) series from DySrAlO 4 oxide. The performed analysis provided a possibility to realize why chemists couldn't get DySrAlO 4 for a long period of time.