To issue tsunami warnings in real-time, complex earthquake sources are usually simplified to uniform slip models for tsunami prediction. Althought this approach of simplification is widely used, its accuracy in predicting tsunami waves in actual events hasnot been fully evaluated and recognized. In this paper, a finite-fault model and various uniform slip models are constructed for the 2021 M _w 8.2 Alaska Peninsula earthquake, and their prediction errors for tsunami waves are compared. The finite-fault model inverted from tsunami datareveals that the coseismic slip of this event was distributed over a depth range of 15 to 40 km, and the ~6m maximum slip occurred near the hypocenter. Besides, the optimum uniform slip model obtained from global search provides very similar tsunami predictions to those given by the finite-fault model, both of which agree well with the observations. Two uniform slip models located at the gCMT centroid but using different scaling relations yield almost the same far-field waveforms.Results of this study show that the optimum predicting ability of uniform slip modelis almost equivalent to that of the finite-fault model. The uniform slip models based on gCMT centroids and scaling relations are relatively reliable for far-field tsunami warning, and difference in scaling relations may not significantly impact the far-field predictions.