[目的/意义]虚拟数字人正成为数字经济时代各行业的新宠，深入识别并分析虚拟数字人用户在线参与行为的需求驱动因素，能为当前虚拟数字人理论研究及运营实践优化提供参考借鉴。[方法/过程]采集B站虚拟数字人初音未来、洛天依、柳夜熙原创视频中用户发布的弹幕文本，运用计算扎根理论方法，结合使用与满足理论，提炼虚拟数字人用户需求因素，并探析虚拟数字人用户需求间关系及对在线参与行为的影响机理。[结果/结论]虚拟数字人用户需求包括情感需求、社交需求、内容需求和审美接受需求，均直接影响用户在线参与行为；内容需求、审美接受需求和社交需求会激发情感需求，进而影响在线参与行为。虚拟数字人运营实践优化策略包括塑造立体饱满的人设形象、打造高质丰富的特色内容、提供实时且持续的情感交互关系等。

[Purpose/significance] Virtual digital human are becoming the new darling of various industries in the era of digital economy. This study deeply identifies and analyzes the driving factors of virtual digital human users' online participation behavior from user demand perspective, which provides reference for the theoretical research and optimi⁃
zation of operation practice of virtual digital human. [Method/process] This study collects the bullet screen text re⁃
leased by the users of Bilibili in the original videos of typical virtual digital human such as Hatsune Miku, Luo Tianyi
and Liu Yexi. Based on the computational grounded theory, combined with the uses and gratifications theory, this study
extracts the demand factors of virtual digital human user's online participation behavior, then analyzes the relationships
between virtual digital human user's demand and the influence paths on online participation behavior. [Result/conclu⁃
sion] Virtual digital human users’demand includes emotional demand, social demand, content demand and aesthetic
acceptance demand, which all affect their online participation behavior. Content demand, aesthetic acceptance demand
and social demand affect users'emotional demand. Several useful optimization strategies from users’demand perspec⁃
tive are accordingly put forward, such as shaping rich and three-dimensional character setting, creating substantial and
interesting personalized content, and providing real-time and continuous emotional relationship.