This paper proposes a method for controlling the topological structures in high-order optical vortices by employing a noncanonical phase structure. The control of the evolutions in high-order optical vortices by using a noncanonical phase structure with a nonuniform azimuthal gradient is studied numerically and experimentally. Results show that the propagation of high-order optical vortices along with a noncanonical phase structure becomes a decayed optical distribution with multiple one-charged singularities along a line. In addition, the control from the noncanonical phase structure can suppress random evolutions of topological structures resulted from the phase noise. These conclusions may indicate a new method to control the decay of high-order optical vortices, and promising potential applications in many fields, such as optical vortices-based optical communications and optical tweezers.