Abstract: The first kind of perpetual motion machine is a kind of imagination machine that without outside external energy input,but it can be able to continue the movement and external work.Recently,some dreamers claim to be able to create a magnetic perpetual motion machine,which uses the magnetic and gravity as the driving force.Based on the first law of thermodynamics,we proved that theperpetual motion machine cannot achieve permanent move.Any scientific research must follow the natural law.The perpetual motion machine that contrary to the myth of the thermodynamic theory is impossible to make out.The thinking and criticism to pseudo-sciencenot only is helpful to correct understanding of science,but also conducive to understand the world.