晚清社会，传统中国迅速而又沉重地开始了它的近代转型，历来被视为中国历史上“三千年未有之变局”。作为最后一代传统史官，恽毓鼎（1862~1918）见证和记录了这个变局。他从光绪十八年开始担任史职，直至清亡，任晚清史官长达十九年。担任过国史馆协修、纂修、总纂、提调、文渊阁校理、日讲起居注官、翰林院侍讲等职位，留下了《恽毓鼎澄斋日记》、《恽毓鼎澄斋奏稿》、《崇陵传信录》等重要著述。本文在全面梳理原始文献的基础上，对晚清史官恽毓鼎作了比较系统的研究： 第一，全面介绍恽毓鼎的生平和社会交往，包括恽毓鼎在晚清担任史官职位的工作概况和进入民国后的社会活动以及他与前辈老师、同道中人、政治人物、外国友人的交往概况，展现一个生动、具体的史官形象。 第二，围绕恽毓鼎的读书生涯，系统梳理其读书的品类，从经史子集、新学书籍和近代报刊杂志等方面分类整理了散见于《澄斋日记》等文献中的史料，深入分析了他的阅读观，包括他的藏书活动、读书之法与读书目的。 第三，重点剖析恽毓鼎的读史、论史和修史活动，尤其是他对历代正史、当代史和史家的评论；整理恽毓鼎进入国史馆后参与修撰《国史•儒林传》的活动，以及恽毓鼎撰写清末信史《崇陵传信录》的经过。 第四，分析作为史官的恽毓鼎对晚清政局和社会变迁的认识，选取了晚清的几个重大政治事件“戊戌变法运动”、“庚子国变”、“辛亥革命”，展示了一个史官对政局的思考。同时，通过恽毓鼎在日记中对日常琐碎生活的描写，分析他对近代中国转型时期社会风尚的认识。

The late Qing Dynasty is a very special and important era of Chinese history, in which dramatic changes took place in every aspects, from the politics to the economy and the culture to the society. Yun Yu-ding is a historiographer of this time who worked for the Qing Dynasty for about 19 years. Because of his job, he had the opportunity to watch the whole progress of major political events which produced significant impact on the Qing Dynasty. He even wrote a book to record what he had seen. My article is bound to study on Yun Yu-ding in an all-around way, including his life, social communication ,reading activities and so on.