诗人白居易一生的思想和创作经历过一次重大变化，从而区分为前后两个不同阶段，前期积极进取精神居主导地位，后期消极独善思想占压倒优势，这几乎是所有白居易研究者的共识。这认识符合客观实际，是正确的。由此引出下一个问题：从前期到后期的转变发生在什么时候？差不多每 Bai Juyi’s life thoughts and creations have undergone a major change so as to differentiate into two different stages: the predominant role of the proactive spirit in the early period and the predominance of the negative monopoly thoughts in the later period. This is almost the consensus of all the researchers in Bai Juyi. This understanding is in line with objective reality and is correct. This leads to the next question: from the early to the late transition occurred at what time? Almost every