This paper first presented modeling methods and procedures aiming to a truck cab and its occupant under blast loading, followed by numerical simulation analysis of dynamic responses of the cab and blast injuries of the occupant by using Ls_Dyna. According to energy history the response duration can be divided into three phases, corresponding to local effect, whole effect and drop down effect. And two schemes for cab blast-resistant design including an aluminum foam sandwich plate and a V-shape deflector were put forward. Using the proposed numerical models, response characters of the two schemes were analyzed, advantages and shortcomings were compared with the initial design. Simulation results show that dynamic responses of cab structure and occupants decrease obviously by using sandwich structure filled aluminum foam, but for a V-shaped deflector it is very difficult to protection the cab structure and occupants simultaneously. And effect of several key parameters, i.e. relative density of foam core, and core thickness were discussed also.