The surge of grocery delivery has changed the grocery retailing industry. Especially due to the current severe situation of COVID-19, people cannot do regular grocery shopping. More and more consumers are turning to the companies in the sharing economy for cost-eective access to goods and services including groceries. In this paper, I use Instacart, an online food-delivery company that does sameday delivery, as an example. I mainly discuss the impact of Instacart on grocery retailers. Specically, I will develop machine learning to build a model to show how to understand the consumer behavior better. In addition, I show some possible solutions with the aid of big data for grocery retailers to problems like balancing demands and supplies.