１９１９年爆发的五四运动，是新旧民主主义革命的分界，是新民主主义革命的开端，这是《中国近代现代史》中明确的历史结论。但历史的发展绝不是偶然的，中国新旧民主主义革命之所以在五四运动时期完成交替，那是前有条件后有表现的。本文试结合五四运动前后的历史史实，对新 The May 4th Movement which broke out in 1919 is the demarcation between the new and old democratic revolutions and the beginning of the new democratic revolution. This is a clear historical conclusion in Modern History of China. However, the development of history is by no means accidental. The reason why the new and old democratic revolution in China was completed during the May 4th movement period was that it was performed after conditions were met. This article tries to combine historical facts before and after the May 4th Movement against the new