本文考字唐代高、睿二朝太子監在政治脈絡中的意義，發現唐代前期，只有武德二年及貞觀朝的太子監國，真正發揮了行政、教育與保障太子地位的作用；從高宗朝以後，雖然監國制度大致上還能如常運行，但它一直與位繼承的政爭或政變相終始，完全失去了它原有的功能。就制度面而言，唐太宗因政變而造就了監國學度之集大成，但此原本立意極美的制度，卻在太宗身後不久就產生質變，竟淪為政治角力的手段。

This article is to invetiage the political meaning of the Gau-tsong and Rei-tsong period in the Tang Dynasty. The crown prince Chien-Kuo in the early Tang Dansty that only in the Wu-te and Chen-Kuan period had the actual function on administration, education and protection of the crown prince, from the Gau-tsong period, although the Chien-Kuo system culd work normally, it always related to the coups of the crown inheritance, and to lost its original function. In system, Tang Tai-tsong built the Chien-Kuo system by coups, but this perfect system was changed when Tai-tsong died, and became the means of political conflict.