摘 要 宦官專權，廢立皇帝，近操朝政，遙控藩鎮，自中晚唐以來，幾成慣例，一次次繼承權的爭奪，引起一次次的宮廷內鬥，宦官集團勢力因之坐大，宦官集團內部亦因利害而分派互鬥。宣宗李忱為為宦官所立，登基之後與宦官共享皇權，是宣宗無可迴避的問題，但如何約束宦官的凶焰，為宣宗即位後的難題與要務。宣宗對宦官之權勢亦思有所壓抑，大中四年，馬植罷相，可視為約束宦官先聲，但宦官勢力深植內廷，關係盤根錯節，宣宗之約束對象亦僅止於宦官之中下階級，上層宦官，仍無法動搖，陳寅恪先生更明白指出，宣宗君臣意圖以閹制閹之策，實屬「計出無聊」。不僅如此，宣宗之死與懿宗之立皆與宦官脫離不了關係。宣宗末，左右軍中尉雖未合為一片，宦官勢力之大與宣宗改革之難竟其功，由此可知。夏侯孜言：「但是李氏子孫，內大臣立定，外大臣即北面事之，安有是非之說？」誠可謂一語中的。

Since the mid-Tang Dynasty, eunuchs dominated emperorship, government, and Fan Shen. The custom had led to successive fighting for power, and endless conflicts. Due to the increasing power eunuchs held, they also divided themselves into groups of respective concerns and profits. Tang Shiuan-Tzung was supported by eunuchs, who thereby shared emperorship together. In view of eunuchs’ domination and greed, Shiuan-Tzung encountered the problems issued immediately after he succeeded to the leadership. The power relation between the emperor and eunuchs went up and down; with Ma-Zie dethroned, however, eunuchs were considered censored and degraded. As eunuchs had developed complex relation in the government, Shiuan-Tzung could only shaken eunuchs of mid and low levels; high-level eunuchs were still uncollapsed. Mr. Chen Yin-Gu even pinpointed that castration planned against eunuchs really achieved nothing. Besides, eunuchs were also closely related to Shiuan-Tzung’s death and Yi-Tzung’s succeeding. During the late years of Shiuan-Tzung, the failed collaboration of the lieutenants armies, as well as the domination of eunuchs, both made impossible Shiuan-tzung’s reformation, which was never beyond expectation.