Abstract: Abstract: To solve the green fruit recognition problem of persimmons and apples, a green fruit segmentation algorithm based on optimized SOLO (Segmenting Objects by Locations) was proposed in this study to achieve accurate segmentation of green fruits in complex environments. The proposed algorithm was a single-stage instance segmentation method, which avoided the disadvantage that detection before segmentation in two-stage methods relied on detection performance. By introducing the concept of instance category, each pixel in the instance was assigned a category according to the location and size of the instance, therefore, the instance segmentation was transformed into a classification problem. This study takes green persimmons and green apples as the research objects. The image collection locations are Shandong Normal University (Changqing Lake Campus) Houshan and the Longwangshan Apple Production Base in Fushan District, Yantai City, Shandong Province. The acquisition device is a Canon EOS 80D SLR camera with an image resolution of 6 000×4 000 pixels. Collect under natural light during the day (7:00-17:00) and under LED light at night (19:00-22:00). A total of 568 images of green persimmons and 498 images of green apples were collected in the experiment, including nighttime, overlap, backlighting, forward light, blocked, and after rain. The collected images were annotated by LabelMe software and then were made into a dataset in COCO format. Specifically, first, split-attention networks (ResNeSt) were used to extract features of the target fruit as the backbone network of optimized SOLO, which enhanced the transfer, reuse, and fusion of features in the front and back layers. Then ResNeSt and Feature Pyramid Network (FPN) were combined to solve the multi-scale problem of green fruits. Because FPN defined allocation strategies for different scale features and assigned them to the pyramid levels optimally. Finally, the image features extracted by the ResNeSt+FPN structure were utilized for the subsequent prediction. The optimized SOLO segmentation algorithm was divided into two branches: category prediction and mask generation. While the semantic category was predicted by the category prediction branch, the object instance was segmented by the mask generation branch, in this way, the target fruit segmentation was completed. The experimental results showed that the average recall and precision of the optimized SOLO segmentation algorithm reached 94.84% and 96.16%, respectively, with an average segmentation time of 0.14 s per green target fruit image on Graphics Processing Unit (GPU). Besides, compared with four algorithms, which were the optimized Mask R-CNN fruit recognition algorithm, SOLO, Mask Region Convolutional Neural Network (Mask R-CNN), and Fully Convolutional Instance-aware Semantic Segmentation (FCIS), the recall of the optimized SOLO segmentation algorithm in this study was improved by 1.63, 1.74, 2.23, and 6.52 percentage points, the precision was improved by 1.10, 1.47, 2.61, and 6.75 percentage points, respectively, and the segmentation times were reduced by 0.06, 0.04, 0.11, and 0.13 s, respectively. The relevant results show that the green fruit optimization SOLO segmentation algorithm proposed by the study can meet the real-time performance of green fruit segmentation and improve the accuracy of green fruit segmentation. This research algorithm can provide theoretical reference for segmentation of other target fruits and vegetables to extend the application of orchard yield measurement and robot harvesting.