By the grand canonical Monte Carlo method,physisorption of hydrogen storage in single-walled boron nitride nanotube arrays(SWBNNTA) at moderate pressure with normal temperature is studied.The influences of tube diameter,distance between tubes and pressure on hydrogen physisorption in SWBNNTA are investigated.It indicates that at normal temperature and moderate pressure the hydrogen storage capacity(mass percent) of SWBNNTA is obviously greater than that of single-walled carbon nanotube arrays,and exceeds the commercial standard presented by U.S.Department of Energy.Corresponding theoretical explanation is given.