Based on a single-pole Debye empirical formula, a multi frequency contrast source inversion (CSI) approach with a multiplicative regularization term is improved tentatively. The main improvement is a modification of inversion object from direct estimation of contrast between Debye scatterers and background medium to indirect reconstruction of four kinds of frequency-independent one-pole Debye model parameters, i.e., the optical relative permittivity, relative permittivity difference, static conductivity, and relaxation time. Two numerical examples confirmed preliminarily feasibility and robustness of the improved method.