This study utilized the SEC (Survey of Enacted Curriculum) method to examine the alignment between Chinese high school chemistry curriculum standards (HSCCS) and the assessment of 'Chemical Reaction Principles' in the National College Entrance Examinations (NCEEs). The HSCCS and NCEEs were coded into two-dimensional matrices separately using SPSS, MATLAB, and EXCEL. The alignment coefficients were analyzed both macroscopically and specifically based on two dimensions: themes and cognitive levels. The findings indicated a generally low alignment between NCEEs and HSCCS in the 'Chemical Reaction Principles' domain, and no statistically significant alignment was observed. Comparing Porter alignment coefficients revealed a gradual increase in the overall alignment level between 2018-2022 NCEEs and HSCCS due to curricular reforms. Further specific analyses and comparisons highlighted significant discrepancies between NCEEs and HSCCS concerning themes and cognitive levels. Regarding themes, 'Ionic Reactions and Equilibrium in Aqueous Solutions' showed substantial alignment between NCEEs and HSCCS. However, for 'Application of Ionic Reactions and Equilibrium' and 'Systems and Energy,' NCEEs diverged significantly from or exceeded HSCCS requirements. Concerning cognitive levels, NCEEs demanded higher levels of student cognition compared to HSCCS.