Abstract: When naphthalene is nitrated with mixed acids, the main product is 1-nitronaphthalene, while its isotner, 2-nitronaphthalene, generally takes up only 5%.It is reported in this paper that by using the Solventized-layer effect to increase the volume of attacking agent, the reaction would be compelled to take place at the less stejic hindered site.Thus, in the direct nitration of naphthalene, the yield of 2-nitronaphthalene may be increased over 40%.