Implicit transform core selection in introduced in VVC Draft 4.0. However there is no unified transform core selection method. In the contribution, two methods are proposed to addressing this problem. With all DST method to unifying ISP and shape adaptive method, -0.01%/xx%/xx% AI/RA/LDB coding gain is achieved with CTC condition (intra MTS on, inter MTS off) and -0.11%/xx%/xx% AI/RA/LDB coding gain is achieved with intra and inter MTS off condition. The ratio adaptive method achieves 0.02%/xx%/xx% AI/RA/LDB coding efficiency differencewith CTC condition and xx%/xx%/xx% AI/RA/LDB coding gain with intra and inter MTS off condition.