[en] The even-even nuclei in the mass A = 130 region exhibit extreme softness to γ-deformation. The change in γ-deformation results in vulnerability to shape polarisation with the addition of an extra nucleon. The previous studies on odd-A Ba nuclei concluded that the quadrupole deformation decreased with increasing neutron number and the γ-deformation changed to a larger extent around ¹³³Ba nucleus. Here, We focus on one of the band in ¹²⁹₅₆ Ba nucleus. In present work, experimental B(M1)=B(E2) ratios were obtained for the previously identified h_11/2 band and compared with the theoretical calculations using the Donau formula. The B(M1)/B(E2) ratios are measured for previously identified h_11/2 band. The rotational limit formalism and the Danau formula are used to calculate the theoretical estimates with and without mixing having K = 9=2 & K = 11=2. The results are in agreement with changing value of γ-deformation