The aim of this study is to indirectly and accurately determine the content of ligustilide, a pharmacological marker in Chuanxiong Rhizoma, through chemical transformation method, and to validate the accuracy of this method using high-performance liquid chromatography diode array detection(HPLC-DAD) specific chromatogram method. During the chemical transformation process, the ligustilide in Chuanxiong Rhizoma can be completely converted into cyclopropyl-ligustilide. By using the reference standard external standard method, the content of cyclopropyl-ligustilide in the reaction solution can be accurately measured, thereby indirectly calculating the content of ligustilide in Chuanxiong Rhizoma. A gradient elution HPLC-DAD method was developed using acetonitrile and 0.1% phosphoric acid aqueous solution as the mobile phase, selecting senkyunolide I, senkyunolide H, coniferyl ferulate, senkyunolide A, ligustilide as indicator components to quantitatively analyze the main active components of phthalein in Chuanxiong Rhizoma. Perform correlation analysis between the peak area of ligustilide and the content obtained through chemical conversion method using specific chromatogram method to verify the accuracy of chemical conversion method. The linear equations (Y=0.000 5X+0.079 2, R=0.996 1) obtained through linear fitting support the accuracy of the chemical transformation method. By measuring the content of ligustilide in 51 samples of Ligusticum chuanxiong from different regions, this study determined that the average content of ligustilide in Chuanxiong Rhizoma was 1.622 ± 0.310%. The research results indicate that the chemical conversion method is suitable for accurately determining the content of ligustilide in Chuanxiong Rhizoma. The findings from the extensive sample analysis provide significant reference for enhancing the quantitative control standards of Chuanxiong Rhizoma in the Pharmacopoeia of the People's Republic of China.