Based on the framework and data of the city digital economy，the digital economy competitiveness of 30 global cities is analyzed. Specifically，the paper focuses on：（1）the scores and rankings of the digital economy competitiveness of major cities；（2）the relationship between city digital economy competitiveness，GDP and GDP per capita，and describe the scores of key cities；（3）the characteristics and dynamics of the digital indicators of each city；（4）Comparison of the cities digital input-output and productivity. Finally，the relevant policy recommendations are put forward.