In order to realize SDI transmission of any resolution video source, a multi-resolution adaptive SDI transmission system with programmable logic device (FPGA) as the core processor is designed. The video resolution detection, multi-resolution processing and other related methods involved in the system are deeply studied. Firstly, on the premise of realizing a 4K (3 840×2 160P@60) transmission system, a 4K video SDI transmission system is realized by using the SQD-square division method. Then, a resolution detection module is added to realize the multi-resolution video adaptive receiving function. Then, a pixel filling module and a cropping module are designed so that the videos with a resolution lower than 1 920×1 080P@60 can be unified into a resolution of 1 920×1 080P@60 and transmitted on the SDI interface. It has been verified by experiments that the system can realize adaptive transmission of videos of various resolutions. Video source types include but are not limited to 4K (3 840×2 160P@60), 1 920×1 080P@60, 1 360×768P@60, 1 280×720P@60, 1 024×768P@60 and other resolutions so that the 4K SDI transmission system has better compatibility, breaking through the limitation that the SDI interface can only transmit limited resolution video.