Nowadays, attention to signs in city has become one of the main concerns of theorists. Using semiotics as a tool to analyze and evaluate metaphor and implicit and explicit implications in city structure is one the applications of urban semiotics. Old structures are more valuable due to having a large number of signs. The cities of Iran which is a developing country have been developed in line with advances in science and technology which has lead to the inconsistencies of streets and squares. According to the Lynch theory, those factors affect the consistency of cities that are in the focus of urban planners. Among these factors are nodes and landmarks that impact on the consistency of cities. The main purpose of this study is to determine the characteristics of urban landmarks in historical cities that are important in the minds of people for the consistency of city structure. Therefore, in the present study, there is an attempt to identify and evaluate different types of signs in Oghada city (which is located in Ardakan county, Yazd province) by a survey and argumentative method using Saussure and Peirce's theory of semiotics. This evaluation was done through completing 100 questionnaires by the residents of aghda city.