A chip for polymerase chain reaction, a method of operating a chip for polymerase chain reaction, and a reaction device are provided. The chip includes: a sample adding region, a mixing region, a temperature cycling region in a sequential arrangement, and at least one driving unit group. The at least one driving unit group includes a plurality of driving units and is configured to drive a liquid drop to move and sequentially pass through the sample adding region, the mixing region, and the temperature cycling region.