NBI fast ion losses in the presence of the toroidai field tipple on EAST have been investigated by using the orbit code GYCAVA and the NBI code TGCO.The tipple effect was included in the upgraded version of the GYCAVA code.It is found that loss regions of NBI fast ions are mainly on the low field side near the edge in the presence of tipple.For co-current NBIs,the synergy effect of tipple and Coulomb collision on fast ion losses is dominant,and fast trapped ions located on the low field side are easily lost.The tipple well loss and the tipple stochastic loss of fast ions have been identified from the heat loads of co-current NBI fast ions.The ripple stochastic loss and the collision-induced loss are much larger than the tipple well loss.Heat loads of lost fast ions are mainly localized on the tight side of the radio frequency wave antennas from the inside view toward the first wall.For counter-current NBIs,the first orbit loss due to the magnetic drift is the dominant loss channel.In addition,fast ion loss fraction with tipple and collision for each NBI linearly increases with the effective charge number,which is related to the pitch angle scattering effect.