The invention relates to a special release agent for fair-faced concrete, which is prepared from the following components in percentage by weight: 60 to 90 percent of decolored oil, 0.1 to 0.5 percent of antirusting agent and 9.5 to 39.5 percent of mineral oil. The method for preparing the release agent comprises the steps that one or two oil products in waste engine oil and edible vegetable oil are evenly mixed in arbitrary proportion and then slowly heated to be between 70 and 80 DEG C; after the oil products to be decolored are evenly mixed, activated clay is added in the mixture for decoloration at a temperature of between 60 and 80 DEG C; the temperature is kept constant for 40 to 60 minutes and then is reduced to be below 40 DEG C; filtration is performed so as to remove impurities; then the mineral oil and the antirusting agent are added, and then the release agent can be obtained after discharging, cooling and filtering materials; or the release agent can be obtained directly by re-compounding the decolored oil and the mineral oil with the antirusting agent. The release agent can allow concrete to be easily demolded, is difficult to erode by rainwater so as to protect reinforcing steel, and cannot pollute the surface of the concrete.