The billets of AM60 alloy,prepared with self-inoculation method,were partially remelted into semisolid state.Effects of process parameters on remelting microstructure of semisolid billet were investigated.Experimental results show that the solid particles obtained with self-inoculation method are in smaller grain size and globular shape after partial remelting,compared with those prepared with other casting methods.In the optimized process conditions,the average size of solid particles of partially remelted billet is 65 μm,and the shape factor is 1.12.The process parameters,i.e.pouring temperature,addition amount of self-inoculants,and the slope angle of multi-stream mixing cooling channel have influence on the microstructure of partially remelted billet.The optimized temperature is from 680 ℃ to 700 ℃,addition amount of self-inoculants is between 5% and 7% (mass fraction),slope angle of multi-stream mixing cooling channel is between 30° and 45°,with which the dendritic microstructure of as-cast billet can be avoided,and the size of solid particles of remelted billet is reduced.