Deaf individuals usually face more challenges in reading and writing, because they are often deprived of adequate spoken input from their infancy. Research on the language features of deaf individuals' writing is abundant. However, their language structures have as yet been unexplored. In order to address this subject, this article uses the holistic approach of complex network theory. This study builds three syntactic dependency networks, the intent being to capture the macroscopic linguistic features in writing of deaf individuals. Three networks are constructed: one is created from a treebank of texts produced by deaf individuals, and the other two are created from two treebanks of spoken and written language samples produced by hearing people. A dependency-based theory of syntax is used. The results indicate that the language system of individuals with deafness is structurally similar to that of hearing people, especially to that of their spoken language, but individuals with deafness tend to have lower language proficiency in both syntactic and lexical aspects. The rigid use of function words and less diversity of vocabulary might be part of the reason for the observed differences.