現代經典研究不免受到民初以來疑古辨真風潮之影響，然在偽真之辨中，失去了晚清以來傳統經學的研究軌跡。特別在春秋左傳學，又具有自經學性質歸向史學價值的大轉折。《左傳》作為現代上古史研究之重要文獻，卻喪失其經之所以為經的傳統重大價值。劉正浩先生秉其師承，接續晚清劉師培、章太炎研究春秋左傳學的研究軌跡，以《左傳》之文與義流行於周秦兩漢，證其不偽，又積極聲張《春秋》乃舊史化新經、《左傳》為鎔史入經之經學性質，以除經史之疑、歸正其本的辯證。本文就其師承、著作研究，與其辨真、春秋左傳學之主張，試作說明。

The studies of Modem Chinese classics influenced by the academic trends in the early Republic of China were different from the traditional academic points of view. In the modem period, ＂Zuo zhuan＂ has been regarded as the historiography. Therefore, the fundamental values of ＂Zuo zhuan＂ which was regarded as Chinese classics by traditional academic were lost based on this point of view. After both Liu Shi-pei and Zhang Tai Yan's studies in the late Qing Dynasty, Liu Zhenghao continued to make his research on traditional classics. He advocated that the content and the truth of ＂Zuo zhuan＂ were popular in the Zhou, Qin and Western Han and Eastern Han Dynasties. Also, he proved the authenticity of ＂Zuo zhuan＂. In addition, he proactively made a clear description of ＂Chunqiu＂ which was originally a historiography and later became a classic. Besides, Liu Zhenghao addressed that ＂Zuo zhuan＂ is an integration of historiography and classics. His argument released the other scholars' query on “Zuo Zhuan＂. In this paper, Liu Zhenghao's inheritance, research papers and assertion will be discussed and interpreted.