In the frozen sand mold computerized numerical control（CNC） machining process， the effective discharge of sand particles generated by cutting sand blanks is one of the key technologies to ensure the quality of sand molding. In this paper， based on the computational fluid dynamics method， a numerical simulation of the sand discharge mode of the surrounded array jet is carried out to analyze the effects of flow rate， target distance， pitch angle and aperture on the flow field around the cavity. CNC machining orthogonal experiments are designed and the range analysis of sand removal rate is carried out to verify the simulation results. High-speed jets form stable attachments on the tool face and cavity walls， and the main area for transporting sand particles is the “sand discharge area” formed by the jets on the cavity wall. Both simulation and experimental results show that the optimal sand removal process parameters are flow rate of 30 L/min， target distance of 45 mm， pitch angle of 65° and caliber of 2 mm， in which the effect of flow rate is the most significant， followed by nozzle caliber， pitch angle and target distance. Results can provide guidance for the optimization of sand removal devices and process parameters.