本文应用散斑干涉技术对四组含纤量分别为０、０．５、１、１．５％的钢纤混凝土三点弯曲裂纹试件的裂纹尖端位移场进行了测试，并换算应变场。测定了全场位移：验证了最大拉应变准则；对含纤量与裂纹扩展阻力的关系进行了探讨。并测定了断裂韧度Ｊ（ＩＣ）。 In this paper, the crack tip displacement field of four groups of steel fiber reinforced concrete specimens with 0, 0.5, and 1.5% fiber content was measured by speckle interferometry, and the strain field was calculated. The whole field displacement was measured: the maximum tensile strain criterion was verified; the relationship between the fiber content and crack propagation resistance was discussed. The fracture toughness J(IC) was also measured.