Traditional laser triangulation measurement has a feature of direction al dependence,so the method can lead to the accuracy decrease while measuring the discontinuous surfaces (ho le plane,step plane,etc.) or cannot measure them.This paper presents a discrete rotational symmetric triangulation s ystem,where the incident laser is the rotation axis,and the emergent light (lenses and mirrors) and receiving sensor h ave the characteristic of circular pattern. Firstly,system′s constraint model and light point & height mapping model are established with the Scheimpflug condition.Secondly,this paper simulates the imaging feature in the conditio n of different depths,analyzes the performance of different subjects′ surfaces when the surface is tilted or s haded,and verifies the superiority that the method can overcome the directional dependence.Finally,the paper establishes t he prototype system and conducts the single-point and step plane experiments.Comparing the contact measurement,the experimental results show that the prototype system can measure the step plane well and has a long measurement range with 0.027mm accuracy at least.