Mobile devices are emerging as working equipment. Developing and maintaining mobile applications for evolving business is costly. Business Process Management technologies enable loose-coupling and composition of services to support the evolving business logic. Business Process Management becomes pervasive and more powerful when it interweaves mobile devices. However, traditional Business Process execution is inefficient in mobile environments: the computational capabilities on mobile devices are various; the movement of devices changes their connectivity. In this paper, we propose a model of mobile computational capability and connectivity. Based on that, we define the constraints of mobile environments and the requirements to execute a business process. A process assignment algorithm and its optimized version considering the cost are designed. Our approach enables more flexible and efficient business process deployment in mobile environments. Preliminary results including a graphical process designer and Android based process engine are tested in a mobile-assisted healthcare project.