The paper investigated the inverse method for the surface materials and the proportions of the space object from long distances based on the scattering spectra. The research results shall provide the data references for space debris detection and forecasting. Firstly, based on the long-distance object detection physical model of scattering spectra, we first constructed the object parameter inverse physical model based on scattering spectra and provided the inverse algorithm for object surface material and its proportion based on the least norm theory method. By combining with the lighting characteristics, object material surface optical reflection characteristics, incidence, reflection and detector angle data, etc., using the multimodal fusion model of the bidirectional reflectance distribution function (BRDF) and characterizing the optical reflection characteristics of the complex material surface. We took the corresponding area in the BRDF as the parameter to be inverted and obtained the inversion algorithm of the object surface materials and its proportion information. Secondly, we performed the experimental validation by building an indoor scattering spectrum detection and acquisition system to perform the scattering spectrum detection and data acquisition of single material and multiple materials with different scales. We intercepted the effective wavelength range of 400~800 nm by preprocessing the scattering spectrum data. Combined with theoretical analysis and inversion algorithm, we took the samples with 4 kinds of materials and performed the material and its proportion inversion with equal proportional and non-equal proportion combination for the samples. The minimum, maximum and average errors of the equal proportion inversion are 0.8%, 13.6% and 4.9%. Moreover, the minimum, maximum and average errors of the non-equal proportion inversion are 6%, 12% and 9.25%. Therefore, according to the above testing results, the maximum average error for inversion is 9.25%. Once considering the error influence of 2.89% from the incidence light source, the maximum average error for inversion will be lower than 6.36%. So we suggested the average inversion error will be less than 10%. Thereby the accuracy of the inverse method is verified. Finally, take one failed satellite as an example. The proposed method was used to invert the materials and proportions of its on-orbit scattering spectra. Its surface materials consist of solar arrays, insulation film and carbon fiber plates, which matches well with the real situation. In summary, this paper has provided a new technical approach for the inversion identifying of space object materials and their proportions from long distances.