Abstract: Superconducting kinetic inductance detectors (KIDs) are considered to be a highly promising technique for the large-scale imaging of millimeter and submillimeter waves in astronomy. As the pixel density and the array size increase, the electromagnetic crosstalk inevitably becomes a problem that prevents increasing the multiplexing during the development of larger KIDs arrays. In this work, an effective method is introduced to suppress the electromagnetic crosstalk and achieve a compact pixel distribution and small frequency intervals. The electromagnetic crosstalk is first analyzed by simulating the behavior of two neighboring pixels, and the physical distance and the frequency interval are optimized. Then, the arrangement of the pixels on the whole array is redesigned using a genetic algorithm to satisfy the requirements. The simulation results reveal that the normalized electromagnetic crosstalk can be reduced to 0.5% on an 8 × 8 array. Larger arrays of 16 × 16 pixels have been fabricated and measured to validate this method, and the results reveal that both the resonance property and survival rate of pixels are improved effectively with this method. This method will be very helpful for designing high-multiplexing KIDs arrays within a limited bandwidth.