Objective Analysis of the diagnosis maneuver of anterior semicircular canal benign positional paroxysmal vertigo(BPPV) and explore the diagnostic mechanism.   Methods The three-dimensional membrane labyrinth model was established in standard space coordinate system, and the otolith in different positions of the membranous labyrinth was set up. The otolith movement in different positions during the Dix-Hallpike maneuver and straight head-hanging test were analyzed based on the physical engine, and the induced nystagmus could be inferred.  Results During the Dix-Hallpike maneuver and straight head-hanging test, the otolith in all positions had a certain degree of movement, and it could induce otolith in the utricle to enter the semicircular canal through the common canal. The occurrence of down-beating nystagmus included the otolith enters the posterior semicircular canal from the utricle, the otolith in opposite posterior semicircular canal move towards the ampulla, the otolith in anterior semicircular canal slide from the bottom to the top of the cupula, and the latter still showed downbeating nystagmus in repeated diagnostic tests. The result  of 10 repetitions were consistent.  Conclusion The diagnostic criteria for anterior BPPV needs to be reassessed. It is necessary to observe the dynamic changes of nystagmus, and the diagnostic maneuver needs to be improved.