This paper mainly explores the design of the multiple key hashing file (MKHF) for orthogonal range retrieval. First, we show the optimal MKHF design problem for orthogonal range queries (ORQs) is NP-hard. Then the performance formula of the MKHF over all possible ORQs is derived. We also present a theoretical lower bound on the performance of the MKHF over all possible ORQs. Finally, a very interesting phenomenon existing in the optimal orthogonal range information retrieval system and the optimal partial match information retrieval system is presented.