With the advancement in technology and emergence of internet together with online platforms especially social platforms such as Instagram and Red,online virtual communities are formed and e-WOM is promoted.During this process,people who present themselves to have in-depth knowledge in a specific field online will gather a group of followers with similar interests.Both parties will interact on the interested topic and relationship is built between them.People with in-depth knowledge are considered to be KOLs.Due to their in-depth knowledge in certain field and their relationship with their followers,their followers view the KOL as one of them and the content shared by the KOLs to be more credible and trustworthy.As such,this gives the KOLs the power to influence their followers and brands start to see the value in engaging KOLs to communicate with their potential customers.Influencer marketing has gained popularity quickly in recent years as they are seen as a cost-efficient marketing strategy to reach audience.Understanding the success of influencer marketing and critical factors that will contribute to the success of such campaigns become essential.Current researches focus on understanding influencer marketing,the theories behind it and factors that contributes to the success of such campaigns.Even though many articles and research papers do acknowledge that relationship of the 2 parties is important and essential for influencer marketing,however,very few or no researches directly conduct empirical analysis on whether relationship between KOLs and their followers indeed influence and to what magnitude influence the success of influencer marketing campaigns and eventually impacting brand’s choice of marketing tactic or KOLs to choose.This study in the form of case study with KOLs on Instagram and Red platform will help to fill this void by addressing this issue which is underexplored currently and provide a deep-dive into the relationship between influencers and its followers and the impact on their followers.Together with the deep-dive,the paper will also include researches on other factors that will affect the effectiveness of influencer marketing.Empirical evidence from this research confirms that KOLs’ ability to influence their followers will impact the outcome of influencer marketing,but only effective through certain methods.Specifically,focusing on two largest social platform,Instagram and Red,the paper found that post content alignment with KOL’s persona and write-up or message interactivity are two influencing factors in determining the success of influencer marketing.While other factors such as relationship built between the KOL and followers does not seem to influence the outcome of future campaigns,potentially suggesting that past relationship built between the KOL and her followers has a short-horizon of influences,as the benefits of strong relationship with the followers seem not carry forward.The findings in this paper offer marketers and KOLs theoretical guidance for conducting influencer marketing campaigns on Instagram and Red as well as in the global and China market.