This paper deals with the dynamic response of sandwich plates subjected to blast load. The sandwich plate is composed of auxetic honeycombs core layer with negative Poisson's ratio integrated with nanocomposite at the top and bottom surfaces. The nanocomposite layers are reinforced by carbon nanotubes (CNTs) where the effective material properties are calculated by Mori-Tanaka approach considering agglomeration effects. Due to the existence of CNTs, the structure is subjected to magnetic field. Based on the Kelvin-Voigt theory, the viscoelastic properties of the structure are considered. The viscoelastic medium is simulated by orthotropic visco-Pasternak model. Utilizing sinusoidal shear deformation theory (SSDT), the motion equations are derived based on Hamilton's principle. Differential cubature method (DCM) in conjunction with Newmark method is used for obtaining the dynamic deflection of the sandwich structure for different boundary conditions. The effects of various parameters such as structural damping, viscoelastic medium constants, geometric parameters of plates, volume fraction and agglomeration of CNTs, duration of blast pulse, geometrical parameters of auxetic honeycombs core and magnetic field on the dynamic deflection of the sandwich structure are investigated. The results reveal that by reinforcing the structure with CNTs, the dynamic deflection induced by blast load decreases about 59%. In addition, with increasing the geometrical parameters of auxetic honeycombs core, the dynamic deflection will be enhanced.