A processor capable of changing redundant processing node comprises a plurality of processing nodes and a plurality of comparators. The plurality of processing nodes comprises a first processing node, a second processing node, and a third processing node, wherein the first processing node performs a first computation, the second processing node selectively performs the first computation or a second computation, and the third processing node performs the second computation. The plurality of comparators comprises a first comparator and a second comparator, wherein the first comparator connects to the first and second processing nodes to compare whether the results of the first computation performed by the first and second processing nodes are identical, and the second comparator connects to the second and third processing nodes to compare whether results of the second computation performed by the second and third processing nodes are identical.