To reduce power consumption and enhance memory-data transmission efficiency, the present invention provides a circuit system for reading memory data for a display device includes a memory, a data bus and a latch circuit. The memory is used for storing pixel data corresponding to a plurality of pixels and outputting the pixel data according to an output control signal. The data bus is used for transferring the pixel data outputted by the memory. The latch circuit is coupled to the data bus and used for receiving the pixel data from the data bus. The latch circuit includes a plurality of latchers and a plurality of logic circuits. The plurality of latchers is used for storing the pixel data. The plurality of logic circuits is used for performing logic operations on the pixel data stored in the plurality of latchers according to a reading control signal.