The invention relates to a POM (Polyformaldehyde) fiber with an anti-carbonation function. The POM fiber with the anti-carbonation function is characterized in that a fiber main body is a polyformaldehyde fiber obtained by melt spinning, an anti-carbonation coating is arranged on the surface of the fiber, the main component of the dried coating is polyethyleneimine and polyvinylpyrrolidone, the mass fraction of the coating is (50-90):(5-35), and the thickness of the coating is 0.2-0.5 percent of fiber diameter or equivalent diameter; in order to accelerate the curing speed of the coating, two silane coupling agents KH550 and KH560 are adopted, and the film formation of the polyethyleneimine and the polyvinylpyrrolidone is promoted through self-polymerization cross-linking curing. After the POM fiber with the anti-carbonation function is added into concrete, the neutralization of the concrete can be restrained, so that the anti-carbonization capability of FRC (Fiber-Reinforced Concrete) is improved.