A method for preparing an alternating arrangement silver-copper lateral composite ingot, including: using a concave roller set; manufacturing a copper frame having a fixed width according to a negative tolerance of a width of the grooves of the concave roller, and corresponding copper bars and silver bars, and performing a surface treatment on the copper frame, the copper bars, and the silver bars; and then arranging different number of copper bars and silver bars at internals as needed and tightly placing into the copper frame to form a composite blank, i.e., a composite ingot. A method for preparing an alternating arrangement silver-copper lateral composite strip is further provided, and the silver-copper lateral composite ingot prepared by the method for preparing the alternating arrangement silver-copper lateral composite ingot is used to prepare the silver-copper lateral composite strip.