Magnetic fluid is one kind of intelligent material with both magnetism and fluidity, which can effectively suspend permanent magnetic mass blocks to improve the friction between the permanent magnetic mass block and the contact surface based on its unique second-order buoyancy characteristics. The function effectively promotes its wide application in electromagnetic sensing, electromagnetic energy harvesting, damping shock absorbers, etc. . This article focuses on the theoretical analysis of the second-order buoyancy of the permanent magnet in a non-submerged magnetic fluid and analyzes the magnetic field and magnetic pressure difference by using finite element simulation. Experiments are implemented to investigate quantitatively the relationship between the suspension height of the permanent magnet and the magnetic fluid injection, suspension force. Comparative tests on the application of magnetic fluid are carried out. The experiment results show that there is a good linear relationship between the magnetic fluid injection volume and the levitation height in the interval of 0. 3~ 3. 4 g. The experimental data are in good agreement with the theoretical results.