Abstract: Double atom Si and Co-substituted AlPO-11 zeolite, CoSAPO-11, was synthesized in situ by hydrothermal method and the Pd/ CoSAPO-11 catalyst was then prepared by incipient wetness method using PdCl2 solution. The isomerization performance of n-butylene on the prepared catalyst was investigated at different temperatures and space velocities. Compared with the traditional commercial Pd/γ-Al2O3, Pd/CoSAPO-11 catalyst exhibits better n-butylene isomerization performance. The results show that at the optimal conditions: 400℃, 5.0 MPa and velocity of 2-4 h-1. The selectivity to isobutylene of the Pd/ CoSAPO-11 catalyst is up to 82.9%-93.1 % with the yield of 31.7%-34.5 %.