Grade Point Average (GPA) is a numerical value evaluating a student’s quality of performance and therefore has the significant figures. In order to obtain the significant figures proper for GPA，we modeled a report card which included sixty-eight total subjects graded respectively with five integral Grade Points (GP)，0，1，2，3，4.The Semester GPA，the Cumulative GPA and their uncertainties were calculated by applying a statistical theory of experimental data processing. We obtained the values of the Semester GPA and the Cumulative GPA which had at most three significant figures between 0.00 and 4.00. This is supported by the obtained values of the uncertainties and consistent with the significant figures of GPA graded in many universities at home and abroad. We should evaluate the student’s performance on the basis of his/her GPA with the proper significant figures.