In the cloud-edge collaborative computing environment, how to allocate appropriate edge computing and cloud computing resources for tasks according to their quality of service requirements is the key to ensuring the effectiveness of cloud-edge collaboration. Aiming at the decision-making problem of offloading tasks with different deadlines in the cloud-edge collaborative system, a strategy of prioritizing tasks based on deadlines and then allocating cloud, edge computing resources, and communication resources based on priority is proposed. The theoretical analysis model and heuristic algorithm are presented, and then the performance of the proposed theoretical model and the algorithm is verified and analyzed through simulation experiments.