Abstract: With DC56D+Z ultra-deep drawing steel as the research object, the material performance parameter analysis of the Ludwik, Swift and Hockett-Sherby hardening models was carried out. The hardening model accurately characterizing the mechanical behavior of the steel was determined. The forming of DC56D+Z steel automobile rear door inner panel was simulated by the optimal hardening model with Hill'48, Barlat'89 and BBC-2005 yield criteria, respectively. The simulation of the material inflow, the maximum principal strain and the maximum thinning rate were obtained and compared with the test results to analyze the influence of different yield criteria on the simulation accuracy. The results show that the Hockett-Sherby hardening model had the highest accuracy in describing the mechanical behavior of DC56D+Z steel, and the square of the fitting correlation coefficient was 0.997 9. The simulation model based on the Hockett-Sherby hardening model equipped with the BBC-2005 yield criterion had the highest accuracy in predicting the material inflow, the maximum principal strain and the maximum thinning rate, with the maximum relative errors of 4.9%, 5.6%, 10.1%, respectively. The BBC-2005 yield criterion was more suitable for the forming simulation of DC56D+Z steel sheets.