The present invention provides a phosphorus-containing compound of formula (I): wherein R1, R2, R3 and R4 are the same or different; and R1, R2, R3 and R4 are independently selected from the group consisting of hydrogen, halogen, C1-8 alkyl, haloalkyl, and alkoxy. The phosphorus-containing compound is prepared by bonding a bisphenol group to a phosphorus atom to prevent the phosphorus-containing heterocyclic molecule from exhibiting steric hindrance on hydroxyl functional groups, thereby increasing reactivity in the subsequent reactions.