Integrating mobile ends (MEs), edge servers (ESs) and cloud servers (CSs) into the collaborative computing structure of End-Edge-Cloud nodes can effectively improve resource utilization and response speed. According to the visibility and accessibility of the cloud server to the MEs, it is divided into two types of computing structures in previous studies, namely parallel structure and serial structure. This paper constructs a hybrid structure based on End-Edge-Cloud node cooperation in mobile scenarios, and studies its task offloading and migration strategy. This hybrid structure absorbs the advantages of both parallel and serial structures, and gives full play to the advantages and synergistic effects of MEs, ESs and CSs. Tasks can be simultaneously offloaded to ESs and CSs in parallel, and tasks can also be offloaded to CSs through ESs. The simulation results show that the average system efficiency of hybrid structure than the serial structure and parallel structure increased by 5% and 28% respectively.