Abstract: Grid computing aims to discover, allocate and coordinate all kinds of service capabilities, which are interconnected by Internet. In service-oriented grid, how to guarantee user QoS (quality of service) requirements becomes increasingly urgent, which is one of the most important study areas in grid computing. In the past, most guarantee mechanisms proposed in the literature concerned more about the guarantee of performance QoS than that of security QoS. This is a relative lack of research on this area. In this paper, we use the concept of GQoP (grid quality of protection)to describe security QoS, and a measurement technology is given to quantize it. We start with definition of quality, description, measurement and mapping of GQoP, which is considered as a subclass of GQoS in this research. And a fusion model about GQoP and GQoS is proposed to resolve the resources conflict between them. Moreover, A GQoP guaranteed QoS adaptive scheduling algorithm is developed and it is adopted into grid system to guarantee user QoS and GQoP. This algorithm regulates QoS grade by each resource provider according to a probability distribution. It can guarantee the usersQoS grade very well, and can also achieve global utility optimum gradually through a constructed Markov chain.