ICT设备因其便携性与普及性促进了多任务现象的发生，研究其发生机理有助于深入了解该现象本质。文章采用网络民族志、深度访谈等方法获取到四类多任务情境下80个视频/图片样本以及16个个案访谈样本作为数据来源。从行为动机、情境相关因素、任务所需资源相关因素、行为结果评价四个方面构建并验证了多任务情境下ICT使用行为的描述框架，解释多任务行为发生机理，重点识别出资源互补型、资源竞争型以及资源交替+互补型三大类ICT使用行为。最后，从图书馆信息职业角度出发，提出环境、资源和服务三点思考，以更好地应对多任务行为对用户和信息职业人员带来的挑战。

Because of its portability and popularity, ICT devices promote the phenomenon of multitasking, and studying its mechanism is helpful to understand the essence of this phenomenon. Firstly, this paper employs online ethnography, in-depth interviews and other methods to obtain eighty video/picture samples and sixteen interviewees in four types of multitasking context as data sources. Secondly, a description framework of ICT-using behavior in the context of multitasking was constructed and verified from four aspects: behavioral motivation, context-related factors, resource-related factors required by tasks, and evaluation of behavioral results, and the mechanism of multi-task behavior was explained, focusing on identifying three categories of ICT use behaviors: resource-complementary, resource-competitive, and resource-alternating & complementary. Finally, from the perspective of library and information profession, this paper puts forward three points of reflections on environment, resources and service to better cope with challenges created by the phenomenon of multitasking for users and information professionals.