Objective The purpose of the study was to evaluate the efficiency of the supine roll test (SRT) and alternative positional tests (APTs) including the bow and lean test (BLT), pseudo-spontaneous nystagmus (PSN), and lying down nystagmus (LDN) to identify the affected side in horizontal canal benign paroxysmal positional vertigo (HC-BPPV). Methods In our prospective study, we performed a testing profile (PSN, BLT, LDN, SRT) on 59 HC-BPPV patients using videonystagmography. We compared the accuracy and sensitivity of these tests in HC-BPPV lateralization. Data from 30 healthy patients were collected as the control group. Results When performing positional tests, the elicited nystagmus coinciding with Ewald's second law was defined as a "positive response". In 44 patients with geotropic nystagmus, the rates of positive response in LDN, PSN, and BLT were 22/44 (50%), 19/44 (43%), and 18/44 (41%), respectively, while in 15 patients with apogeotropic nystagmus, the positive response rates of these three tests were 10/15 (66.7%), 9/15 (60%), and 4/15 (27.00%), respectively. The sensitivity of LDN (54.38%) was higher than that of PSN (47.37%) and BLT (38.60%) but lower than that of SRT (89.47%). Notably, the accuracy rate of PSN (71.8%) was higher than that of the other APTs. In 6 patients with symmetrical nysgtamus during the roll test, 5 patients showed a positive response in both LDN and BLT (83.34%), whereas 4 patients showed a positive response in PSN (66.67%). Conclusion All positional tests are helpful for determining the affected side of HC-BPPV, but SRT carries the highest accuracy of lateralization followed by PSN.