Abstract: Hydrothermal crystallization method was used to synthesize Co-substituted aluminophosphate molecular sieves (CoAPO-11). The results of XRD, SEM, FTIR, N2 adsorption-desorption analysis and UV-visible spectroscopy show that Co is incorporated into the framework. CoAPO-11 possesses Lewis and Brnsted acid sites, and the latter is important for skeletal isomerization. Isomerization reaction results of 1-hexene over CoAPO-11 molecular sieve show that the temperature and space velocity have a significant influence on the reaction. The catalyst shows good isomerization properties at around 300℃ and space velocity of 2.4h－1.