張玉穀頗留意「虛」、「空」作比的靈動性，對此於詩歌結構中的作用有普遍關照，並顯現「比」多重變化的效果，時露對幽微詩意的深化提點，大量展現空靈的美感傾向，足見張非表面形式批評。此外，張玉穀對「比」中之新奇手法、奇思異想多所費心，並藉由對「用筆」的闡發，精細呈現詩作清和平遠中之離奇變化。張對「比」中的「古趣」之評則多顯現含蓄古樸中不失活潑而蘊含餘味之貌。《古詩賞析》「比」多「興」少有其文藝企求與示人為學的考量。就「比」發展流脈而言，張玉穀繼承沈德潛溫婉之際，未將「比」與沈所看重的寓託傳統、含蓄手法密切連繫，而多呈現「比」靈活變宕之態。張玉穀對詩作之文藝關懷、詩法之落實闡說亦可見格調派本身詩學體系之推展。

Zhang Yu-gu pays great attention to the agility of Bi (comparison) with the effect of emptiness in poetry. He has a general concern for the function of Bi in the structure of poetry. In addition to the demonstration of effects of multiple changes of Bi, he has a deep explanation of subtle parts of poetry and exhibits an ethereal aesthetic tendency, showing that he is not just a surface-level critic. Besides, Zhang pays attention to novel techniques and whimsical ideas in Bi. By revealing writing techniques, he delicately presents the peculiar changes in poems of peace and tranquility. Zhang's comments on Gu-Qu in Bi not only are lively in its simplicity and quaintness but also bring endless reverberation. The reason why Appreciation of Ancient Poems provides more explanation for Bi than for Xing (affective image) is because of the pursuit of literature and art, and the consideration of teaching people how to write poetry. From the perspective of the development of Bi, Zhang Yu-gu inherits Shen De-qian's gentleness but no longer closely connects Bi with traditional and implicit techniques, which valued by Shen De-qian. Instead, he presents a flexible and varied appearance of Bi. From Zhang Yu-gu's concern for the artistry of poetry and his specific explanation of poems through poetry composition, we see the advance of the poetics system of Ge-Diao School.