The article is devoted to the analysis of the author’s assessment realization through the syntax in the framework of the scientific discourse. The author’s involvement in oral and written texts belonging to the scientific dimension is implied with the help of diverse linguistic means at different language levels and one of them is expressiveness that can be represented through the category of modality. Modern studies have proved that scientific discourse expresses the author’s evaluation of the problem under research by phonetic, lexical, syntactic and other means. The degree of the author’s evaluation reveals his pragmatic attitude to what he states and sheds light on the emotional state of the addressee. Using various linguistic means of expressing modality, the scientist is influenced by the postulates for justifying an opinion which strengthens the specific cultural context of scientific presentation. Nevertheless, it is through the syntactic level having close interconnection with the content of the utterance that the implicit assessment can be revealed. An important purpose of the article is to identify syntactic means used in scientific discourse that express the author's modality on the basis of scientific literature of linguistic dimension. The research approach of the mixed-method research approach with general theoretical and linguistic analysis of scientific literature, semantic, deductive and quantitative analysis of the data collected illustrates the classification of syntactic means possessing the author's assessment. As a result, it is possible to single out six syntactic means of modality. The results obtained in the course of our research are of practical value for further research of scientific discourse, the accurate communicative behavior for representatives of the scientific community. Moreover, they contribute to the hypothesis about the evaluative constituent of scientific discourse, stating that the language of scientific specificity cannot be considered purely devoid of any kind of objective narration.