Abstract: A physical modelling system is developed to study the pull-out mechanism of embedded soil anchors using transparent soil and particle image velocimetry (PIV). In the system, two different continuous ball shape anchors are set in the experiment to observe displacement impact areas, soil displacement, load-displacement curve and shape and location of pull-out failure interface. After analyzing the ultimate bearing capacity and the failure mechanism of the soil anchors, a suggested method is given. From the results, based on the circumstances of this model, the maximum vertical displacement impact areas have direct relationship with the radius of the ball and the distance between the balls during pull-out of the soil anchors. The continuous ball shape soil anchors (type A and B) can effectively provide 52% and 117% more force than the normal cylinder anchors. The pull-out force of the continuous ball shape soil anchors can be divided into three different parts: adhesion on shaft, end bearing in clay and cohesive through clay.