An automatic biochemical analyzer, comprises a reaction wheel comprising an inner ring and an outer ring, wherein the reaction wheel is equally divided into multiple cuvette positions; the inner ring and the outer ring have a photoelectric detection position, a sample injecting position, a reagent injecting position, a sample stirring position, a reagent stirring position and a cuvette cleaning position; the photoelectric detection position of the inner ring is offset relative to that of the outer ring by a first cuvette position along a counterclockwise or clockwise direction; and the sample injecting positions, the reagent injecting positions, the sample stirring positions, and the reagent stirring positions of the inner ring are offset relative to those of the outer ring by a second cuvette position along the same direction, the first cuvette position is equal to the second cuvette position, or a difference between those two is one cuvette position.