Abstract: On the basis of fracture mechanics, the problem of reflection crack in half rigid pavements is studied in this paper by use of isoparametric finite elements method. And by introducing singular elements, Stress intsnsity factors at crack tip are calculated.The function of stresses absorbing membrane to prevent refletion crack from growinq is investigated.Nume rical results show that the shear stress is the main cause of producing reflection crackin half rigid pavements. Laying a stresses absorbing membrane between surface layer and basic layer can prevent reflection crack from developing to a certain extent. Moreover, the material with properties of small Young’s modulus, large permissible strain and non-britlleness under low temperature is most suitable for the stresses absorbing membrane.