In order to obtain more precise icing thickness distribution within a span, a special icing monitoring technique for tight tube Optical Fiber Composite Overhead Ground Wire (OPGW) is proposed and preliminary verified by experiments. This method utilizes the distributed strain sensing capability of Brillouin optical time domain reflectometer. The strain distribution of OPGW was obtained by measurement, and then the weight distribution was derived based on mechanical analysis method. the specific icing thickness distribution was obtained via the conversion between weight and icing thickness. In the simulation with a suspended optical cable, the errors of the experimental results are 2.27% and 15.77% for two uniform loadings of 5 kg and 2.5 kg, which preliminarily verifies the effectiveness of the proposed method. The error analysis shows that the effect of the proposed method is better for longer span range in practice, because it allows longer spatial resolution which can improve the strain measurement accuracy.