We present herein the first all-electron relativistic internally contracted multireference configuration interaction with Davidson correction (icMRCI+Q) study on the low-lying states of fluoroiodo carbene, CFI, which contains the most electronegative element (fluorine) and the heavy halogen (iodine). The potential energy surface (PES) of the first excited singlet state ((A) over tilde (1)A '') of CFI was carefully examined along the C-I bond distance at the icMRCI+Q/ANO-RCC level, while the other two geometric parameters were optimized at every C I bond length in contrast to fixing them at the equilibrium values. A reliable barrier height of the (A) over tilde (1)A '' state was determined to be 625 cm(-1) by our high-level icMRCI+Qcalculations with large ANO-RCC basis set and with inclusion of the spin-orbit coupling, core-valence correlation, and zero-point-energy. Finally, the electronic states of CFI with vertical transition energy up to 6 eV were studied. The calculation presented here will provide more comprehensive results about the structure and behavior of electronic states of CFI radical.