Fiber Optic Taper(FOT) array coupled digital X-ray detector is an efficient way for large-area high-resolution X-ray imaging applications, but the coupling method between the small ends of FOT array and the corresponding image sensors is commonly tightly glued coupling at present. To avoid the disadvantages in the conventional glued coupling method, a fine adjustable non-glued 2×2 FOT array coupled digital X-ray detector was designed and implemented. The proposed X-ray detector scheme can realize multi-dimensional adjustment of the four data acquisition boards on the same adjusting layer through the novel horizontal and vertical adjusting mechanisms, with the restriction of the limited adjusting space formed by the structure of the FOT array and the sizes of the printed circuit boards, and especially under the condition of the distance between the boards was only 40 mm in the vertical direction. According to the fact that the four data acquisition boards and the data transmission board are separated, an embedded Ethernet data acquisition system for multiple CMOS image sensors based on one ARM chip and four FPGA chips was implemented. Tested results showed that the implemented X-ray detector with the imaging area of as large as 100mm×100mm, can realize fine adjustable non-glued coupling and data acquisition of multiple CMOS image sensors, which could be a new way for multipurpose use in large-area high-resolution digital X-ray imaging applications for scientific researches.