Objective To investigate the application value of different magnetic resonance imaging (MRI) sequence examinations in the evaluation and diagnosis of T staging of patients with bladder cancer. Methods 128 patients with bladder cancer confirmed by surgery and pathology who were treated in the hospital during May 2013 to October 2014 were selected as the research objects. The patients raceived different MRI sequence examinations. The surgical or pathological examination results were taken as the gold standard to evaluate the differences in specificity, sensitivity and accuracy of conventional MR scan, conventional MR scan with diffusion weighted imaging (DW-MRI) scan, conventional MR scan with DW-MRI scan and dynamic contrast enhanced (DCEMRI) scan of three kinds of MRI sequence examinations in the diagnosis of T staging of patients with bladder cancer. Results Among the 128 cases of patients with bladder cancer who received surgical or pathological examination, there were 83 cases (64.8%) diagnosed as without bladder wall muscular layer invasion and 45 cases (35.2%) with bladder wall muscular layer invasion . 43 cases with muscular layer invasion were correctly diagnosed by routine MR with DWI and DCE-MRI. 75 cases without muscular layer invasion were diagnosed correctly, including 8 cases with false muscular layer invasion and 2 cases without. The diagnostic accuracy, specificity and sensitivity were 92.2%, 90.4% and 83.6%, respectively, which were significantly higher than 77.3%, 75.9%, 80.0% of conventional MR and 83.6%, 81.9%, 86.7% of conventional MR with DWI (81.9%/86.7%), and the differences were statistically significant (P<0.05). Conclusion To apply conventional MR scan with DW-MRI scan and DCE-MRI in the evaluation and diagnosis of T staging of patients with bladder cancer can effectively improve the diagnostic accuracy and effectiveness, which has positive effect on saving consultation hours, improving the efficiency of diagnosis and treatment and comprehensively improving the prognosis of patients. It is worthy of clinical promotion.