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Quadratic band crossing points (QBCPs) and quantum anomalous Hall effect (QAHE) have attracted the attention of both theoretical and experimental researchers in recent years. Based on first-principle calculations, we find that the FeB
2
monolayer is a nonmagnetic semimetal with QBCPs at K. Through symmetry analysis and
k · p
invariant theory, we find that the QBCP is not protected by rotation symmetry and consists of two Dirac points with the same chirality (Berry phase of 2
π
). Once introducing Coulomb interactions, we find that there is a spontaneous-time-reversal-breaking instability of the spinful QBCPs, which gives rise to a
C
= 2 QAH insulator with orbital moment ordering.