(La0.6Ce0.4)65Al10Cu25 bulk metallic glasses (BMGs) were prepared by copper-mold casting. The crystallization behavior and thermal stability of (La0.6Ce0.4)65Al10Cu25 were investigated by X-ray diffraction and differential scanning caloricity (DSC) after being annealed at its supercooled liquid region under the pressure ranging from ambient pressure to 1015 MPa. Results show that pressure promotes crystallization of (La0.6Ce0.4)65Al10Cu25 BMGs. The onset crystallization temperature Tx decreases with increasing of preannealing pressure at a slope of –5.17 K/GPa, and the apparent activation energy of the crystallization Ep determined by Kissinger equation increases with increasing of preannealing pressure. The influencing mechanism of preannealing under pressure on the crystallization of (La0.6Ce0.4)65Al10Cu25 BMGs were discussed in the view of Gibbs free energy and chemical short range order.