Zhihu Live, a knowledge paid product, is a special virtual product of real-time interactive voice experience. Information seekers cannot obtain complete content before making payment decisions. Therefore, they need to evaluate the perceived usefulness of Live information through systematic and heuristic clues to make payment decisions. After acquiring complete knowledge, users will score or evaluate user satisfaction based on the difference between perceived usefulness before the payment stage and actual quality of knowledge. Zhihu Live allows speakers to describe knowledge in text and voice. Based on this, this paper explores how heterogeneous information features transmit different clues, enhance users' perceived usefulness of information, and then influence the final user satisfaction of the product. Combining the Information Foraging Theory, Information Acceptance Model and Heuristic-Systematic Model, we set up knowledge characteristics of heterogeneous information on the impact of user satisfaction measurement model of knowledge paid product, and to test text and voice characteristics effect on user satisfaction, and the moderating effect that theme features have on user satisfaction.