During the process of strip hot rolling production,finish rolling thickness accuracy is a critical indicator reflecting the product quality.Strip thickness control involves complex models with multivariable,strong coupling,and nonlinearity,it epitomizes precision in Level 2 control for hot strip rolling.Practical production often experi-ences thickness defects due to diverse,intricate causes.Current analysis heavily relies on manual post-analysis,which is challenging and inefficient due to the complexity involved.In response,an automatic traceability model for thickness defects in hot-rolled strip was developed,which focused on strip products with head thickness defects,identified and analyzed their mechanisms,and traced the primary causes behind these issues.The expertise of ex-perienced numerical modeling experts was integrated.By delving into the model mechanism underpinning strip thickness control and clarifies the coupling relationship between strip thickness and rolling parameters,the study presented an analysis workflow for tracing thickness defects of hot-rolled strip,featuring core analysis modules addressing issues such as inaccuracies in roll gap and rolling force models,as well as anomalies in rolling model parameters.Finally,the strip data of 1 780 mm hot strip mill in a steel plant for three consecutive months were used for model performance test.The results demonstrate a 90.27%accuracy in tracing thickness de-fects of the strip,effectively meeting actual production requirements.This achievement signifies the successful automation of thickness defect tracing in strip hot rolling,leading to a significant improvement in analysis effi-ciency.