To study the structural damage characteristics of marine soft clay under lateral unloading path,stress path tests under lateral unloading condition on the clay obtained from Ruian, Wenzhou were carried out to study the influence of lateral unloading path and structure on stress-strain relationship, shear strength, initial tangent modulus, and other typical mechanical properties. The influences of stress path and soil depth on initial structure and characteristics of structural damage were analyzed. The experimental results show that the structure of Wenzhou soft clay is strong and its stress-strain relation is obviously strain-softening. Under lateral unloading condition, the initial tangent modulus is linearly related to the average consolidation pressure, and the slope is 1.4 times that of the loading condition. The corresponding strain at peak strength of shear stress is smaller than that under loading conditions. The stress ratio structural parameters of soft clay under lateral unloading condition were presented.The results show initial stress ratio structural parameters under lateral unloading condition is obviously larger than those under loading condition. The structural damage curves can be divided into three sections: smooth damage, accelerated damage and deceleration damage.The structural damage rate under loading condition in accelerated damage section is faster than that under lateral unloading condition. The difference of structural damage rate which needs more attentionis related to the anisotropy of soft clay.