The present invention relates to a process for preparing nanoporous VSB-5 molecular sieves, and more particularly, to a process for preparing nanoporous VSB-5 molecular sieves useful as a hydrogen storage material, a catalyst, a catalyst supporter and an adsorbent, performed in such a manner that low-cost inorganic base or monoamine instead of a template essential in the conventional process is, as a pH modifier, incorporated into raw materials comprised of nickel and phosphorous compounds and crystallized to give VSB-5 molecular sieves in an economical and efficient manner.