Alibaba Group has multiple business groups covering e-commerce, cloud computing, digital entertainment and many other fields. The strength of these business groups varies in different time periods and scenarios, so it is difficult to simply give a strongest judgment.

From the perspective of revenue scale, Alibaba Group's core e-commerce business group has always been the strongest, accounting for the majority of Alibaba Group's revenue. Aliyun, Alibaba's cloud computing business group, has also developed rapidly in recent years, becoming a leading company in China's cloud computing market and making a lot of contributions to Alibaba Group.

In addition to revenue scale, the strength of Alibaba Group's various business groups can also be considered from multiple aspects such as brand value, market influence, and strategic position. This requires comprehensive consideration of multiple factors for evaluation.