$H{eta}$ (core)/SAPO-11 (shell) composite molecular sieve was synthesized by the hydrothermal method in order to combine the advantages of $H{eta}$ and SAPO-11 for the methylation of naphthalene with methanol. For comparison, the mechanical mixture was prepared through the blending of $H{eta}$ and SAPO-11. The physicochemical properties of $H{eta}$, SAPO-11, the composite and the mechanical mixture were characterized by various characterization methods. The characterization results indicated that $H{eta}$/SAPO-11 composite molecular sieve exhibited a core-shell structure, with the $H{eta}$ phase as the core and the SAPO-11 phase as the shell. The pore diameter of the composite was between that of $H{eta}$ and SAPO-11. The composite had fewer acid sites than $H{eta}$ and mechanical mixture while more acid sites than SAPO-11. The experimental results indicated that the composite exhibited high catalytic performances for the methylation of naphthalene with methanol.