Pumice was used to make up lightweight aggregate concrete (LWAC). Frost resistance durability of LWAC in 5% Na2SO4 solution was studied. The test results showed that LWAC durability deteriorates more rapidly under freezing-thawing in salt solution than in water. The strength loss of LWAC was reduced by steel fiber and polypropylene fiber regardless of Na2SO4 solution and water. Fly ash and silica fume can improve Interfacial Transition Zone（ITZ）and the frost resistance of fibers reinforcement LWAC dramatically.