Yazdi dialect is one of the oldest and richest central languages of Iran, which is more different from the standard Persian dialect in terms of phonetic features and use of local and historical words,But in some cases, it also has morphological and syntactic coordinates. In this paper, in a descriptive, analytical and martyrdom method, to study the main rules and characteristics of phonetics, morphology and syntax, such as: Phonological processes, types of verbs, tenses and aspects of verbs, construction and types of nouns, types of personal and impersonal pronouns, adjectives, adverbs, letters, descriptive and derivative verbs and numbers of Yazdi language are discussed. In the analysis of the mentioned rules, descriptive grammar methods and valid sources of linguistics and grammar have been used. In the use of word types, in addition to the differences due to the phonetic features of the native dialect, in terms of the use of a number of verbs, such as: Isundan /? Isundæ, n /, Heshtan /heš, tæ, n/, khosbidan /xosbidæ, n/, nouns, adjectives are also frequent. There are differences in the use of the suffix (ok: ok) compared to the standard dialect. In Yazdi dialect, the fractional number is mainly obtained from the repetition of two prime numbers,So that the larger number is the first and the smaller number is the second.