Abstract: Sub-pixel mapping technology is significant to land cover information extraction and development of quantitatively agricultural remote sensing. Sub-pixel mapping accuracy is affected not only by sub-pixel mapping model, but also by many other factors such as reconstruction scale, pixels spatial relationship and image spatial resolution. These factors increase complexity and uncertainty of sub-pixel mapping results. At present, most relevant researches mainly focus on sub-pixel mapping model itself but research on influencing factors of sub-pixel mapping accuracy is ignored. Therefore, in this paper, analysis on main influencing factors of multispectral remote sensing image sub-pixel mapping accuracy was carried out. The study region located at the junction area of Taonan County of Baicheng City in Jilin Province and Tuquan County of Xing'an League in Inner Mongolia Autonomous Region. Among them, Spatial Gravity Model (SGM) was applied in the sub-pixel mapping experiments which was one of the mainstream model in present sub-pixel mapping research field. Both 8 m and 16 m spatial resolution GF-1 multispectral remote sensing images were used as the data sources which were in the same sensor and had the same spectral resolution. Effects of reconstruction scale, pixels spatial relationship (touching, quadrant, surrounding) and image spatial resolution on the sub-pixel mapping accuracy in experiments were studied thoroughly. In the experiment of 8 m spatial resolution GF-1 remote sensing image, when sub-pixels was in touching spatial relationship and degradation scale was five, the experiment could achieve the best result of sub-pixel mapping. The overall accuracy and Kappa coefficient of 8 m spatial resolution remote sensing image reconstruction from 40 m spatial resolution remote sensing image were 74.67% and 0.604, respectively. In the experiment of 16 m spatial resolution GF-1 remote sensing image, when sub-pixel was in quadrant spatial relationship and degradation scale was four, the experiment could achieve the best result of sub-pixel mapping. The overall accuracy and Kappa coefficient of 16 m spatial resolution remote sensing image reconstruction from 64 m spatial resolution remote sensing image were 74.65% and 0.623, respectively. By analyzing sub-pixel mapping accuracy range caused by reconstruction scale, pixels spatial relationship and spatial resolution, the overall accuracy maximum range of these three factors were 18.08%, 4.39% and 0.08%, respectively. The corresponding Kappa coefficient maximum range was 0.268, 0.049 and 0.006, respectively. Therefore, by analyzing the sub-pixel mapping model mechanism, the order for affecting sub-pixels mapping accuracy based on SGM model was reconstruction scale > spatial resolution> pixels spatial relationship. The experiment results of this paper could provide a reference for choosing sub-pixel mapping models, setting model parameters and selecting the appropriate remote sensing data to obtain better sub-pixel mapping accuracy.