This study aims to shed light on the status of Persian thesauri of Humanities and to evaluate them in terms of four dimensions of form construction, semantic relationships, displaying controlled vocabularies, and management systems, based on the latest version of the ANSI/NISO z39.19 2005 standard. The research method utilized in this study is the analytical survey method. Systematic sampling method was used to select samples of the terms contained in the latest edition of every thesaurus in the field of Humanities except Islamic sciences thesauri. So the number of thesauri in this study was 3, and they were ASFA, UNESCO and thesaurus of Sociology. The research instrument used in this study was a check list defined in Microsoft Excel. The samples for the four dimensions were entered in the checklist and were evaluated on the basis of the relevant standards. The results of the study shows that the level of observance of semantic relations standards in ASFA, UNESCO and thesaurus of Sociology were respectively 93%,99% and 99%.The level of observance of form construction standards in ASFA, UNESCO and thesaurus of Sociology were respectively 99%, 99.5% and 96%. The level of observance of the standards in ASFA, UNESCO and thesaurus of Sociology was respectively With regard to displaying controlled vocabularies dimension were respectively 84%, 43% and 54.5% and the level of observance of management system standards in ASFA was 82% while the rate of this dimension in the remaining two thesauri was 14%. Finally, it is concluded that possessing the required expertise, familiarity with the standards of thesauri construction, utilizing appropriate models, taking the needs of the end users into consideration, reviewing and revising information storage and retrieval policies, and activation of the indexing and the reference sections of the libraries for registering the users' documents are among the major factors that if observed can lead to the construction of more effective and efficient thesauri.