A computer automatic data acquisition and control system which can be used for data acquisition and reduction of temperature field during high rate directional solidification(HRS) process has been developed. The system has been applied to the investigation of DD98 single crystal superalloy solidification process. The result shows that the data are stable and the problem of interference at workshop is resolved, the solidification parameters, such as temperature gradient, width of mushy zone, are variable with the stationary heating temperature and withdrawal rate. The temperature gradient is highest in the starting stage and becomes stable during the late stage of solidification. The width of mush zone is increased in the solidification process.