Traditional three-dimensional optical data storage is limited by the defect of inefficiency due to its serial written mode. To overcome this disadvantage, a modified parallel optical data storage system is proposed. This system utilizes Digital Micro mirror Device (DMD) as spatial light modulator, through which the incident light is modulated as designed. In succession, the emergent light is focused respectively by a microlens array, giving rise to a controllable focal spots array. The system is modeled and simulated by ZEMAX and Matlab, and the design of a microlens array based on the parameters of the existing system is also demonstrated. At last, the result of the simulation is presented in this paper, from which the conclusion that this system could realize parallel data storage with optical switch is drawn.