The fairness of curves and surfaces has been used in the shape design of industrial products more and more widely. With the wide applications of T-splines in the surface modeling, this paper analyzes the fairness of T-splines and gives some fairness properties of standard T-splines and semi-standard T-splines. For some special Tsplines, this paper proposes a method of comparing the T-spline fairness. The research will contribute to the relevant research of T-spline fairing algorithms, and will contribute to the applications of T-splines in computer-aided manufacturing.