Fair-faced concrete protective agent has excellent waterproof performance and excellent environmental protection performance. It can greatly prolong the service time of buildings being built with fair-faced concrete. For drawing the accurate conclusion that protective agents effects on carbonation resistance of fair-faced concrete, the test for the effect was done with permeable water-soluble silicone protective agent and acrylic film forming agent for protection. The test results show that both film forming agent for protection and permeable water-soluble silicone protective agent can effectively reduce the carbonation depth of fair-faced concrete, and the function of film forming agent for protection is better than that of permeable water-soluble silicone protective agent. Both the carbonation depths of test pieces coated with two different types of protective agents decrease along with the increase of curing age. Curing age and permeable protective agent can act separately while curing age and film forming agent for protection can boost each other, and the carbonation depth of fair-faced concrete can be further reduced because of the mutual action between the curing agent and the film forming agent for protection. A prediction model of the carbonation depth of fair-faced concrete was built. The influences of type and thickness of protective agents on carbonation resistance of fair-faced concrete were considered while being built.