A cube body comprising four U-shaped frames, each of the four U-shaped frames has two rectangular corners and two open ends, wherein a first connection is arranged at each of the two rectangular corners and perpendicular to the two open ends, the two open ends are provided with a second connection which is insertable into the first connection of another one of the four U-shaped frames, each of the two rectangular corners has a first magnetic bead inside, a first engaging structure is arranged on each inner side of each of the four U-shaped frames. A magnetic cube roller coaster comprising the said cube body and a magnetic plain plate is also provided.