Abstract: The extensive use of the er (儿) construction in Beijing dialect has profound meaning and characteristics of Beijing dialect. This paper makes a diachronic study of the er construction in Beijing dialect from the perspective of structural form and grammatical meaning. The research shows that the suffix structure produced from the Tang dynasty, and erhua as well as the predicative er-structure originate from the Yuan dynasty. After that, the er construction was transformed and fused during the Ming and Qing dynasties, and finally it comes into the language system of Beijing dialect. Thereinto, the period of the Yuan and Qing dynasties have exerted a great influence on the emergence and development of the er construction and there might be some permeation of the language of Mongolian and Manchu within it.

Key words: the er construction in Beijing dialect, historical syntax, language contact