Abstract: The second generation of high temperature superconducting tapes composed of rare earth (Re), barium (Ba), copper (Cu) and oxygen (o) are collectively referred to as REBCO tapes. The tapes have a wide application prospect in high field magnets due to their high critical current density, good mechanical strength and electromagnetic properties. However, when the REBCO tape is in a variable external magnetic field, the vertical component of the magnetic field can penetrate the transverse part of the tape and generate a non-uniform and time-varying screening current field (SCF). Thus, the SCF can have a great impact on the high-accuracy field magnets. In this paper, a flexible like-round core quasi-isotropic high temperature superconductor structure was proposed, and its SCF in different orientations, magnitudes and excitation rates of external magnetic field at 77 K was calculated by using the finite element method. Then, the conductor sample was tested under the same conditions as the simulation, and the experimental results were consistent with the simulation results. The simulation and experimental results of this paper can provide a reference for the design of high field magnets in the future.