Bike share usage patterns and its impact on people’s travel behavior have been widely studied in recent years. In the past, researchers have focused on understanding spatial and temporal patterns of bike share usage, differences of bike share usage among different demographic and socio-economic groups and factors influencing bike share ridership. However, since the outbreak of COVID-19 in 2020, people have changed their lifestyles and travel needs significantly with the start of working from home, reducing recreational activities and avoiding taking public transit. Therefore, this research looks into the change of bike share usage before and after the COVID-19 outbreak, using Philadelphia Indego bike share as a study context. This study adopted a multilevel mixed-effect linear regression model that incorporates demographic, built environment, meteorological and temporal factors to compare the effects of these factors before and after the COVID-19 outbreak in determining bike share ridership. Three key results were found in this study: 1) trip purpose and spatial distribution have shifted from commuting to residential recreational trips, 2) bike share gained more popularity during warm weather, and 3) bike friendly infrastructure became more important than before in determining bike share ridership. Findings of this study are useful to bike share providers, urban planners, and local officials for understanding the differences in recreational biking and utilitarian biking and how bike share programs can better address the needs of residents during the pandemic and in a post-pandemic world.