We report in space experiments about the use of magnetic force, which is generally shown by the product of density (ϱ), weight magnetic susceptibility (χ), magnetic field strength ( H ) and its gradient ( dH / dy ). The magnetic force caused by strong permanent magnets was proved to induce buoyancy and convection in μ G as follows: (1) Transport of bubbles in fluid: In most fluids which are diamagnetic, the magnetic buoyancy force could transport bubbles toward a stronger magnetic field. Collision and fusion of two bubbles was also observed. (2) Magnetic Support of Chemical Reaction (2H 2 O 2 → O 2 +2H 2 O on Pt Catalyst): In μ G, the decomposition reaction continued smoothly when O 2 bubbles were removed from the surface of catalyst by magnetic buoyancy force. In the absence of the field, the reaction was observed to stop. (3) Magnetic Support of Combustion in Diffusion Flames: Magnetic convective air flow could support combustion in μ G.