Abstract: Taking CBA teams in the last 10 seasons (2005～2015) as a case, and applying HHI method in Economics to the analysis of the data in cross section, time sequence and panel, the author measures and reveals the uncertainty of CBA teams’ competition power and explores the uncertainty’s relation to audience, winning percentage in home and away competitions and net scores. Results demonstrate that the CBA HHI value gradually decreases in the past 10 seasons, which indicates that the CBA teams’ competition power is developing towards a balanced state, while the competitive gap between the teams is still significant; The gap between home and away winning percentage is quite significant (P< 0.01), and the CBA spectator attendance rate is negatively correlated with HHI value (P<0.05), that is, the more uncertain the result is, the higher is the rate of attendance, the gap in net score between home and away teams in the past 10 years is gradually narrowing, and the champion and the runner up are becoming close in their strength, but both champion and runner up is significantly stronger than the rest teams in strength.

Key words: CBA, HHI, Competition Power, Uncertainty