Embodiments of the present disclosure provide a method for testing performance of GPU, a terminal device and a storage medium. The method comprises: capturing a target scene from a 3D scene model by a main camera in the 3D scene model; determining an execution sequence of functions in a script object of the target object and determining a target rendering process according to the execution sequence; obtaining a target image via the target rendering process, and incrementing a rendering execution number i by 1; moving the main camera, capturing a new scene to update the target scene and iterating the above steps until i is equal to j; obtaining a time period T for completing j target rendering processes, and determining a target performance parameter according to j and T; and determining a performance test result of the GPU according to the target performance parameter and a performance criterion parameter.