To verify whether the difficulty design of college English textbook reading texts aligns with graded teaching requirements and CET-4 proposition criteria

this study takes 48 reading texts from

New Navigation English

(Book1

&

2) and

New Future English

(Book1

&

2) adopted by Guangzhou College of Commerce

with the June 2025 CET-4 reading texts as reference. Using Flesch Reading Ease (FRE) and Flesch-Kincaid Grade Level (FKGL) as core indicators

plus average characters per word and average sentence length as auxiliary metrics

the study measured readability and conducted one-way ANOVA via Microsoft Word and SPSS 27. Results show both textbook series follow progressive difficulty design:

New Navigation English

(Book 1) (the least difficult) is suitable for CET-4 transitional training;

New Future English

(Book 1) (CET-4 equivalent difficulty) serves as basic CET-4 preparation material; the second volumes of both series (above CET-4 difficulty) are for advanced training. Significant differences in readability and average characters per word only exist between

New Navigation English

Book1

&

2

with no statistical differences among other textbooks. This study provides quantitative references for college English textbook selection

adaptation and reading teaching difficulty design.