Improving the hydrothermal stability of zeolites promises attractive benefits for catalytic applications, especially in the case of nanosized zeolite. In the present study, a two-stage synthetic method, conducted at low (95 degrees C) and high (210 degrees C) temperatures sequentially, was developed to prepare nanosized SSZ-13 zeolite with enhanced hydrothermal stability. The crystal size was tuned within 50-300 nm by simply controlling the period in either stage. In addition, compared with the microsized counterparts, the nanosized SSZ-13 zeolite showed remarkably enhanced hydrothermal stability with exhibiting equivalent catalytic performance in the selective catalytic reduction of NOx by ammonia (NH3-SCR). The improved hydrothermal stability of nanosized zeolite was due to the structural healing by the high temperature treatment. (C) 2017 Elsevier Inc. All rights reserved.