WMS (Workflow Management System) are gaining popularity in recent years. Most scheduling algorithms developed for WMS focus on a single QoS requirement or a single workflow. However, WMS should serve for many users. And different users have different QoS requirements, the scheduling algorithm should be developed for multiple workflows with different QoS requirements. The scheduler should satisfy every user's QoS requirements and find an optimal schedule. In this paper, we introduce a Multiple QoS Scheduling Strategy of Multi-Workflows (MQSS) to address this problem on the basis of our previous work. Experimentation shows that our strategy is able to increase the scheduling success rate and find an optimal solution.