Live-stream selling is becoming increasingly common on e-commerce platforms.It provides merchants with a channel to reach new consumer groups. In practice, there are two modes of live-streaming selling: merchant live-streaming and influencer live-streaming. However, many brand manufacturers still collaborate with influencers while opening merchant live-streaming. This collaboration brings a larger consumer base to the brand, but it may also result in additional costs and demand erosion due to the loss of pricing power. This paper establishes a stylised model of the livestream e-commerce supply chain to investigate the conditions for cooperation with influencers and the trend of price changes with influencer attributes. Our main finding is that whether to collaborate with influencers depends on the commission rate paid and the additional potential market that influencers can bring. Secondly, the changes in retail prices are related to the additional market brought by live streaming rooms and the commission rates of influencers. Interestingly, we found that in collaboration with influencers, the prices of both channels will decrease as the commission rate increases.