晚近學界均以張湛為東晉玄學的代表人物，然而對其學說評價卻褒貶互見，導致看法歧出的關鍵應在於學者對張湛宇宙觀內容的掌握。本文將仔細辨析張湛《列子注》中「無」字的雙重指涉，以及「虛」字的二層義涵。試圖藉由對「無」字的分析，說明張湛對玄學本無論、自生說的修正。另一方面則藉由對「虛」字的剖析，詳述張湛以「虛」為軸心，融合佛、道思想及兩漢元氣論，建立獨樹一幟的宇宙觀。由是可知，張湛並非只是雜糅諸說，而是對舊有玄學諸說作批判性繼承，並融合道、佛思想塑成一家之學。對玄學的發展而言，張湛之學有破有立，唯其在義理開展的深度上仍嫌不足，實不宜斷然否定或肯定其說。

　　　　　Modernly, all in the academic circles conclude that Zhang Zhang was a typical personage of East-Jin philosophy. However, there are conflicting assessments (praise or disparage) for his theory. The main reason should be that the scholars differ each other in the comprehension of Zhang zhan's cosmology. In this article, we study Zhang Zhan's Annotation on Lei-tzu, and proceed to distinguish and analysis his "Wu" and "Shiu". We hope that on the one hand, we can discuss Zhang Zhan's critical heritage of Wei-Jin philosophy; on the other hand, we interpret the concept of "Tay Shiu" which Zhang Zhan established. By those, we argue that Zhang Zhan blended various thinkings harmoniously in his theory but failed to spread out the profundity of the principles in order to decide afresh the position of him in the history of Chinese philosophy.