The invention discloses a swing mechanism of a bionic intelligent robot fish. A fish body with a streamline shell and a fish tail are included. The fish body comprises a first part, a second part and a third part. Gaps of 2-5 mm exist between the first part and the second part, between the second part and the third part and between the third part and the fish tail sequentially. The first part and the second part, the second part and the third part, and the third part and the fish tail are connected sequentially through a first steering engine, a second steering engine, a third steering engine and a rail roller type connecting rod device, friction force between swing mechanisms is further reduced, and overall energy consumption is reduced.