A novel cast processing method, self-inoculation method(SIM), was proposed. The process involves the addition of self-inoculant to melt, then pouring the melt to a mould through a multi-stream mixing cooling channel. In this paper, the process parameters were investigated. Results indicate that the melt treatment temperature, the amount of self-inoculant added, and the slope angle of the cooling channel are the key factors for SIM process. The optimized parameters are that the melt treatment temperature is between 680 and 700℃;the addition of self-inoculant is between 5wt.% and 7wt.%;and the slope angle of the cooling channel is between 300 and 450. Further analysis reveals that SIM changes the solidification microstructure of slurry by controlling the nucleation and growth of the primary phase in the melt.