太子監國，本是國君不在朝的情況下所實行的權宜之計，亦即以皇太子代替國君「監理國政」。先秦的太子（世子）監國，是以「君行」為前提，其出發點是著重於行政的考量，以維持國家體制的正常運作。本文考察六朝隋唐太子監國制度的適用時機、太子監國的地點、東宮官的角色、監國的公文格式、監國的行政運作等問題，發現在六朝大量出現的太子監國，已有了新的意義和內容，與先秦時的監國制度大不相同。發展到唐代，監國制度更趨於合理而完善，唐太宗因政變而監國，他在監國期間的一套做法，具有為後世建立典範的意義。

The expedient, crown prince Chien-Kuo, means that the crown prince supervises the state for the emperor’s absence. By the emperor’s going out, it started with administration for keeping up the system working normally before the era of Ch’in Dynasty. This article is to examine its applying time, its occasion the role of the heir apparent, the form of official document, its administration operation in the six and Sui-T’ang Dynasty. Being different from Chien-Kuo system before Ch’in Dynasty, it changed meaning and had new contents in the six Dynasty. Till T’ang Dynasty, Chien-Kuo system became more reasonable and perfect. After Emperor T’aitsung’s coup d` etat, he supervised the state and built model for later generation in the period of his supervising state.