▎ 摘　　要

Uniform nitrogen-doped graphene lines with favorable outlines are essential components for graphene-based functional devices. However, the line instability in the droplet printing process would deteriorate the straightness and uniformity of printed lines. In this work, straight and uniform nitrogen-doped graphene lines were precisely fabricated by elaborate regulation of drying and overlapping process between neighboring droplets. The bulging instability and jetting instabilities in the printing process were eliminated at a moderate substrate temperature. The wavy edge and outline fluctuations of printed lines were characterized and reduced by decreasing droplet spacing. The uniformity and consistency of printed lines were enhanced by overwriting multilayers. To the best of our knowledge, a systematic and effective way for the printing of uniform nitrogen-doped graphene lines with favorable outlines was revealed for the first time. This study sheds light on the fabrication of straight and uniform nitrogen-doped graphene lines, which might be employed in the droplet printing process of graphene and other functional materials.