Concrete is one of the most important, widely used and low price building material with suitable ductility in construction industry. Due to the vast application of concrete, growing need of cement production and its harmful environmental effects such as emission of 7% of in atmosphere and considerable consumption of energy, it is important to provide an alternative production in order to move through sustainable development. One strategy is to produce a concrete which is more compatible with environment. One solution for reduction in OPC consumption is using alkali activated binders. Concrete rapidly loss their strength in a less time than the service life considered for them under distractive environmental condition. In some structures such as dams, powerhouses, bridges and tunnels which have longer service life and in many cases the cost of repairing and taking care of them is more than their initial building cost this problem is gotten more important. Freezing and thawing is one of the physical destructive factors and if a concrete has not enough resistance regarding freeze-thaw cycles, it will deteriorate in a time period much shorter than its service life. However concretes with higher compressive strength usually are more resisters against physical and chemical harmful environment attack, but some other factors such as permeability and internal structure denseness could have excessive influence in concrete durability. The aim of this research is investigating of metakaolin and polypropylene fibers effect on alkali-activated slag concrete resistance and durability in freeze-thaw cycles. Alkali-activated slag concrete is a mixture of activated Isfahan steel plant slag by alkaline solution containing sodium hydroxide, sodium silicate and conventional aggregates gaining. According the aim of this study which is investigating of fiber and metakaolin effect, a constant mixture design is used and the single variable parameter is quantity of fibers and metakaolin. In preparation of mixture designs a basic design without metakaolin and two other designs with 10 and 20 percentage of metakaolin replacement were used. Other designs were obtained by adding 0.1, 0.3, 0.5 and 0.7 volumetric percentage of polypropylene fiber to the three explained design. So by considering all mixtures mode 15 mixture designs were used. 22 cubic specimens with dimensions of 10 cm were made from each mixture design and experiment of compressive strength and freeze-thaw cycles tests were done on them. The specimens were tested under freezing and thawing conditions according to ASTM C666 B standard. To compare the mixtures against freeze-thaw cycles, the change in length, weight and water absorption ratio and compressive strength of specimens were analyzed after end of freeze and thaw cycles. The results of experiment showed that adding of 10 % metakaolin improve durability and compressive strength. Also using of 0.1% fiber improve durability of concrete against freeze and thaw. Keywords Alkali- activated slag concrete, freeze-thaw cycles, compressive strength, polypropylene fibers and metakaolin