Many urban residents have recently lost their jobs due to the COVID-19 pandemic, which has made employment vulnerability in cities attained attention. It is thus important to explore the relationship between urbanization and employment. This study quantitatively analyzes spatiotemporal evolution and data correlation of urbanization and vulnerable employment, and explores the role urbanization plays in vulnerable employment by using historical data on 163 countries in the period 1991-2019 to test the theoretical hypothesis. The results show: It's clearly observed that there is a high correlation between the rate of urbanization and that of vulnerable employment, and the examples of G7 and BRICs are for it. The estimated urbanization yields a negative and statistically significant regression coefficient (-0.168), indicating that urbanization has a negative effect on vulnerable employment. If the urbanization rate increased by 1 %, the rate of vulnerable employment decreased by 0.168 %. The rural-urban sector conversion and changes in employment relationship driven by urbanization account for this. Countries with different income groups or populations have reacted differently to the rise in urbanization. Vulnerable employment in higher-income countries has been more significantly affected by the rise in urbanization, and more populous countries are more sensitive to it as well. These findings provide evidence for how urbanization promotes employment and decent work.