An image stitching method in the complex environment of non-structural context was studied. The anthurium image mosaicing under greenhouse environment was achieved. A random ridge by natural light environment in greenhouse was researched. An anthurium image stitching method based on SIFT only was improved by using a method that extracting anthurium by a 2G-R-B method firstly, and registering image by SIFT method secondly. The proposed method can greatly reduce the computation and processing time under high-noise environment. And a quickly and efficiently anthurium extraction method under high-noise environment was achieved. Experiments were carried on intelligence target spaying system. The results showed the mosaic time-consuming was 0.083s and false positive rate was 7.3%.