Nowadays, a number of methods on model-based user interface development (MBUID) have been applied to deal with the diversity of users, devices, environments, and development platforms in a pervasive computing environment. In general, those methods attempt to specify a user interface once on an abstract level, and to run anywhere by use of model transformation. Due to the limitation of task model used in the current MBUID methods, however, it is still an open question whether the generated user interfaces can meet usability requirements in a divergent context of applications. In this paper, a task model based user interface development framework is proposed for modeling and implementing effective, efficient and satisfactory user interfaces. In order to cope with the usability requirements, a novel perceptual control theory based task analysis (PCTBTA) method is presented to specify the user tasks in a divergent environment, in which the context information is introduced into the task analysis process, and the interaction content is reflected at a higher level of abstraction, providing the task space for usability design. For model transformation, a method is provided for converting PCTBTA task model into a variety of interface models. Finally, a case study is provided to illustrate the feasibility of the proposed method, and the effectiveness of the method is demonstrated by comparing it with other methods in terms of availability and performance.