A mask plate is disclosed. The mask plate includes a via hole pattern, the via hole pattern includes a body portion and at least two protruding portions extending outward from the body portion; a dimension of the body portion is greater than a resolution dimension of an exposure machine, and each of the protruding portions includes a first protruding portion having a dimension greater than the resolution dimension of the exposure machine. Upon exposure of the mask plate, the protruding portions themselves and zones between adjacent protruding portions form convex portions and concave portions of a via hole, respectively; in this way, a circumstance and also an edge area of the via hole as formed is increased and an electric resistance of the via hole is reduced effectively.