The invention relates to the technical field of automatic liquid mixing and discloses a liquid mixing method and device. A container encapsulated with various solutions is vertically fixed on a support plate, and the container moves along the arc using the support plate at the center in a reciprocating manner so as to achieve solution mixing. The liquid mixing method and device have the advantages that multi-station, large-capacity and arc-reciprocating type mixing is achieved, mixing of large-capacity solutions can be achieved by the unique mixing manner and device structure, and the requirements of the mixing of the large-capacity solutions are satisfied.