徐渭的书法虽然外表粗服乱头，实则天真烂漫，不失法度。徐渭对书法有比较系统的 认识，对执笔、用笔等书写技巧有细致的讨论，并且提出了鲜明的审美主张。他在构建理 想中的书法体系时，主张由心出发，以心的主体力量去带动实践。执笔要“识深浅长短”， 须“双指苞管”并“悬腕”，且执笔不宜太紧，“执紧必滞”。行笔时要劲笔涩行，正侧并用， 不使笔锋全然藏起以致“媚隐”。他创造性地阐释古人关于笔法的描述，认为有些是描述运 笔动作，如“飞鸟出林、惊蛇入草”，有些是描述点画形态，如“屋漏痕”，运笔动作与点 画形态如同形与影的关系。 徐渭崇尚书法艺术的“媚”，而媚的风格指向并不单一，既可指倪瓒书风的“古而媚”， 也可指赵孟頫书风之媚趣，而达致“媚”的趣味又需相应的用笔技巧。他期望书法可以通 过学习以达到“天成”，天成的境界是不依傍他人，成全自我的真性以展现“真我面目”。 徐渭所崇尚的“真我”正是他看做书法艺术首要因素的“心”。从执笔、用笔技巧到“媚” 的审美取向，皆归于创作主体的“心”。徐渭所建构的以心为本的书法理论，既是个人反叛 精神的表现，也是阳明心学影响下的时代产物。 

Xu Wei's calligraphy, although the appearance of rough clothes, is innocent, without losing the law. Xu Wei has a systematic understanding of calligraphy, detailed discussion of writing skills such as grasping and writing, and puts forward distinct artistic ideas. In constructing the ideal calligraphy system, he advocates starting from the heart and driving practice with the main force of the heart. Writing should be “at the time of movement” in order not to be stagnant, and must be “double-finger tube” and “with the wrist raised”. Line brush when strong brush acerbity line. The front and side of the brush are used together, do not make brush front completely hide so that “Mei Yin”. He creatively explained the ancient description of the brush method, and thought that some of them described the movement of the brush, such as “flying birds out of the forest, startled snakes into the grass”. Some described the form of the painting, such as “house leakage marks”, and the relationship between the movement of the brush and shape like the shape and shadow. Xu Wei advocates the “Pleasing” of calligraphy art, but the style of Pleasing is not single. It can not only refer to Ni Zan's “ancient and beautiful” style, but also to Zhao Mengfu's charming, and the interest of “Pleasing” needs corresponding writing skills. He expected that calligraphy can be learned to achieve “Tiancheng”, the realm of “Tiancheng” is not to rely on others, the true nature of the self to show “true self ”. The “true self” advocated by Xu Wei is the “heart” which he regards as the primary factor of calligraphy art. From writing, writing skills to aesthetic orientation of “Pleasing”, all belong to the author's “heart”. The theory of mind-based calligraphy constructed by Xu Wei is not only the expression of individual rebellious spirit, but also the product of the times under the influence of Yangming psychology.