Primacy ratio is one of the important criteria to measure the impact of the first city in a country or region，which reflects the characteristics of urban size and the driving force，influence and radiation of the primate city in the region. This paper deeply studies the changing trend and development status of the primacy of Zhengzhou city. Through the two-city index method and multi-city index method，it makes a comparative analysis of the population primacy ratio and economic primacy ratio of Zhengzhou and some cities，finds out the gap between Zhengzhou and other cities，and puts forward some countermeasures and suggestions to improve the primacy of Zhengzhou city.