question: Increasing farmers’ income is one of the objectives of rural revitalisation in China. As a direct selling channel, live streaming has become immensely popular and demonstrated unprecedented growth worldwide. Farmers were able to increase their income by selling farm products on live streaming sales platforms, especially after the COVID-19 outbreak. With the support of online payment and smartphone technology, promotion methods are constantly innovated, among which random rewards are widely used on live streaming sales platforms. This study aimed to examine if and how random rewards optimise farmer’s income from live streaming sales. We observed that random rewards have a positive effect on optimising farmers’ income from live streaming sales, which was verified by mathematical proof and numerical analysis. The results show that there is a threshold that provides a normative guide to farmers on whether they should sell at a discounted price in live streaming sales with random rewards. More importantly, we found the mechanism of how random rewards maximise farmer’s income from live streaming sales. This study also provides suggestions of concrete actions for farmers and policy makers.