Although long noncoding RNA TUC338 has been characterized as an oncogene, its role in bladder cancer is unknown. The purpose of the present study is to investigate the function of TUC338 in bladder cancer. We found that TUC338 was upregulated in early-stage bladder cancer patients and showed early diagnostic values. After surgical resection, plasma levels of TUC338 were significantly downregulated. Moreover, microRNA 10b (miR-10b) was also upregulated in bladder cancer patients. TUC338 and miR-10b were positive and significantly correlated in bladder cancer patients, but not in healthy controls. Bladder cancer cells with TUC338 overexpression showed upregulated miR-10b, while miR-10b overexpression failed to significantly affect TUC338. TUC338 and miR-10b overexpression significantly promoted bladder cancer cell invasion and migration. Therefore, TUC338 may promote bladder cancer at least partially by upregulating miR-10b.