Taking the fiber type and its volume fraction as variables， the uniaxial tensile properties of sea sand engineered cementitious composites（SECC） were studied through uniaxial tensile test. Based on the existing tensile constitutive model of engineered cementitious composites（ECC）， the steady-state cracking mechanism of SECC was expounded. The fluctuating rising and falling segments of the tensile stress-strain curves of SECC were attributed to the strengthening and softening， and a new tensile constitutive model suitable for SECC was obtained. The results show that polyethlene （PE） fiber/SECC with 1.5% fiber volume fraction exhibits the strain hardening behavior of saturated multi-crack， and the ductility can reach 3.99%. The proposed SECC tensile constitutive model can accurately describe the tensile stress-strain relationship of SECC with steady cracking behavior.