The aim of this study is to analyze the parallelism between Italian nominal phrase and clauses after finding out the existence of similarities of the two structures by applying linguistic theories recently developed and extremely subdivided to the various phenomenons in the functional categories. In the first section, based on the definitions and classification of the functional category in Italian noun phrases and clauses comparing other languages within the comparative syntactic perspective, I focused on the phenomenons like the ambiguity of quantifier`s meaning in Italian noun phrase and clauses and the omission of the functional head C (head of the complementizer phrase) and D (head of the determiner phrase). Concerning to the position and meaning of adjectives and adverbs in the noun phrases and clauses, I analysed that meaning of adjectives and adverbs depends on their locations in the functional structure which shows the syntactic hierarchy of the functional categories in the nominal and clausal structure. Therefore the change of semantic meaning of adjectives and adverbs, their word order constraints and their syntactic licensing in the structure will be a important evidence to demonstrate the syntactic similarities for the existence of the parallelism of the nominals and clauses in Italian syntactic structure. Finally, I tried to reconcile the word order of adjectives and adverbs that appear in the Italian noun phrases and clauses to the universal word order. The derivation of universal word order from the surface word order of adjectives and adverbs can be explained with the phenomenon of noun movement and verb movement respectively in the noun phrase and clauses. Each movement is the head movement belong to the same type of movement phenomenon. Therefor also this shows well the parallelism between noun phrases and clauses in Italian.