Silver behenate nanocrystals were first prepared by chemical precipitation in a water tert-butyl alcohol mixed solvent. The influence of main factors on the silver behenate crystal size was studied. The morphology, crystal structure and ther- mal behavior of silver behenate nanocrystals were investigated using SEM, TEM, XRD, IR and TG-DTA. These results showed that the preparation method, reaction temperature and excessive silver ion con- centration in reaction solution played important roles in determining the size of silver behenate nanocrys- tals. The prepared silver behenates were scaly crys- tals with a mean diameter of about 70 nm. The silver behenate nanocrystals possessed layer structure. A series of structural changes of silver behenate nanocrystals were observed at different temperatures. The silver behenate nanocrystals had excellent thermal stability below 120℃. At high temperature there were two distinct transitions resulting in dra- matic structural changes. In the first transition at 138℃, the alkyl chains of silver behenate were trans- formed from an ordered into a disordered state. In the second transition at 230℃, a completely irreversible structural change took place due to the decomposi- tion of silver behenate nanocrystals. The influence of main factors on the silver behenate crystal size was studied. The morphology, crystal structure and ther- mal behavior of silver behenate nanocrystals were investigated using SEM, TEM, XRD, IR and TG-DTA. These results showed that the preparation method, reaction temperature and excessive silver ion con- centration in reaction solution played important important roles in determining the size of silver behenate nanocrys- tals. The prepared silver behenates The silver behenate nanocrystals were observed at different temperatures. The silver behenate nanocrystals were observed at different temperatures. The silver behenate nanocrystals had excellent thermal stability below 120 ° C. At high temperature there were two distinct transitions resulting in dramatist structural changes. In the firs t transition at 138 ° C, the alkyl chains of silver behenate were trans- formed from an ordered into a disordered state. At the second transition at 230 ° C, a completely irreversible structural change took place due to the decomposi- tion of silver behenate nanocrystals.