過去學界對宇文護的研究較為薄弱，且受《周書》記載的影響，對宇文護執政期多是抱持著腐敗、專權等較為負面的評價。然作者會田大輔發現墓誌、文集、佛教史料等正史之外的文獻對宇文護的評價都十分正面，這種記載上的矛盾便激起其研究宇文護執政形象的構想。作者從宇文護執政時期的幕僚選用情況著手，分別從其天官府、中外府及晉國公府等三個單位的幕僚進行分析，認為當時政界並非如過去想像那樣為「親宇文護派」與「親周帝派」之間的對立關係，反之宇文護在選用人才時對各界勢力多有考慮，包含西魏以來的元勳及其子弟、關中漢族甚至是結怨者，均有所任用。這不但反映宇文護用人之度量與遠見，也妥善融合西魏北周內部各方勢力，對維持西魏北周國祚有相當貢獻，且其選用之人才與西魏及周末隋初時期均有相當之延續性，顯見其用人並不若過去想像之偏頗與專擅。由此可以看出，宇文護執政期的形象並非如此負面，且其對北周政權之延續亦有貢獻。

Research on the rule of Yuwen Hu is scarce and suffers from the highly negative evaluation in the History of Zhou (Zhou shu). On the contrary, relatively positive comments about Yuwen Hu are found in other documents, such as epitaphs and literary and Buddhist writings. This essay analyzes Yuwen Hu’s staff, including the tien-guan-fu (天官府 ), the zhung-wai-fu (中外府 ), and the Jin-guo-gong-fu (晉國公府 ). By discussing the personnel composition of staff in the above three organizations during the period of Yuwen Hu’s rule, the author demonstrates that apparent conflicts between “Yuwen Hu’s clique” and “Zhou Empire’s clique” in political circles did not exist. On the contrary, the nobles of Western Wei, the Han in Guanzhong, and even his political foes were all installed by Yuwen Hu. This not only means that Yuwen Hu was magnanimous, it also shows how he integrated each clique into the Northern Chou. In addition, we find a continuity between the appointments of Yuwen Hu and those of the Western Wei and Sui. Therefore from the constitution of his staff we can understand the positive contributions of the reign of Yuwen Hu for the Northern Zhou.