Work-based learning is a crucial approach to promoting professionals’ working and learning efficiency. It is just-in-time, work-related, informal and spontaneous. Aiming at facilitating this kind of learning, in the paper, we propose WoBaLearn, a work-based learning system, which can provide professionals just-in-time, personalized and work-related learning supports. This paper specifies the design of learning process in WoBaLearn based on a previous designed architecture. For evaluating the system, a learning scenario, in which professionals engage in a work-based learning activity with the support of WoBaLearn, is assumed and implemented. Results obtained from the scenario evaluate positively the design of WoBaLearn.