越公房是弘农杨氏较有代表性的一个房支，其兴起自北魏，发展于隋、唐。作为以军功起家的士族，弘农杨氏越公房追随北魏孝武帝西入关中，成为宇文泰所建立关陇集团的重要成员，在西魏北周至隋代的政治中发挥着重要作用，在唐初也具有一定的影响力。在科举制度的影响下，弘农杨氏越公房在唐代的发展道路出现了巨大的转变：其仕进之路逐渐由凭借军功居高位转变为以科举入仕，与此相应，其身份逐渐由中古时期的“旧士族”转变为统一大帝国的“新官僚”；其生活重心亦逐渐脱离地方乡里而转移至两京，并在累世同居的基础上，由郡望转变为城市中的“坊望”。本文以唐代弘农杨氏越公房的五个主要支系为研究对象，对其世系进行梳理，对其仕进之路进行考察，并在此基础上，着重分析其在唐代的仕宦发展特点；同时，还原和再现越公房向城市迁居的过程和城居生活的状态，并对越公房修行、新昌、靖恭、履道四大坊望的形成原因试作初步探讨。本文主要以仕宦和城居生活两大方面为中心，探讨中古士族弘农杨氏越公房在唐代的发展演变历程。

Yue-gong-fang is a representive brench of Hong-nong-yang-shi. Yue-gong-fang rised at the dynasty of North Wei, developed in the Sui and Tang dynasties.As an noble which had grown up by Military force, Yue-gong-fang became an important number of the GuanLong group, and played a big role in the Sui dynasty and at the beginning of the Tang dynasty.Under the influence of imperial examination system, Yue-gong-fang developpde and tended to bureaucrat and urbanisation.It changed from noble of ancient times to the bureaucrats of the Unified Empire.It gradually leaved the villiages for the cities and changed from the Jun-wang to the Fang-wang in the cities. In this thesis, the author selected five major brenches of Yue-gong-fang as the objects and drew out the family trees of them. On the basis of this, the author made analysis of the official career of the family numbers, recovered the process of the family’ migrition to the cities and revealed how they lived in the cities. At the same time,try to find out the reason why the Fang-wang formed. In this thesis, the author mainly researched how Yue-gong-fang had been developping in the Tang dynasty as noble of the ancient times from the angles of bureaucrat and urbanization, and to find out the details of the societal changes in the Tang dynasty.