In this work, we constructed a two-transmitter, two-receiver array based on grid-controlled modulated X-ray tubes and plastic-scintillator-coupled SiPM detectors to improve the communication rate of X-ray communication (XCOM) systems. The effects of various working parameters, and array dimensions on the bit-error-rate of the system were investigated. We derived the relationship between array dimensions and spatial correlation coefficient theoretically, and pointed out that a higher spatial correlation coefficient is the main reason affecting system performance experimentally. The array communication system achieves a communication data rate of 3.6 Mbps under a 12.5 cm laboratory atmospheric channel with a moderate spatial correlation coefficient of 0.5. The array XCOM system can effectively increase the data rate compared with previous work. This study can provide an experimental foundation and design reference for the establishment of a multiple-input, multiple-output array XCOM system.