High field magnets built using low temperature superconductors are currently approaching their upper field limit of 25T or so. Applications of (RE=Y, Gd)BCO coated conductors for the generation of high magnetic fields are increasing sharply, this while (RE)BCO coated conductors themselves are evolving rapidly. This present study simulates the stability of a new magnet made of ring-shaped YBCO coated conductor sheets. The current sharing temperature, minimum quench energy (MQE) and normal zone propagation velocity (NZPV) are calculated by using the power law model. Without winding process and bending strains, this HTS magnet made of superconductor sheets is considered to have advantages of good stability, simple structure, easy fabrication and minor effect of flow capacity.