The mini-seedling graft method of Hevea brasiliensis is widely used in the breeding of high-quality rubber tree seedlings due to its advantages such as a short nursery period, low labor intensity, large number of seedlings per unit area, and well-developed main roots of seedlings. However, the seedlings of rubber trees budded in autumn and winter require more time for the scions to germinate after graft survival, and the grafted mini-seedlings grow weakly, which diminishes the advantages of the mini-seedling graft method. Therefore, it is crucial to find appropriate technical measures to improve the germination rate and growth rate of the seedling scions. In this study, the effects of grafting time and topping time on the sprouting and growth of scions in grafted seedlings of rubber tree were investigated, specifically focusing on the seedlings grafted in winter with the variety H. brasiliensis reyan879. Grafting time significantly affected the survival rate, sprouting rate, seedling height, and nursery release rate of the grafted seedlings (P<0.05), with seedlings grafted in November showing significantly higher survival, sprouting, and release rates than those grafted in October, while the seedling height at the two leaf-umbrellas was significantly lower for November-grafted seedlings. Topping time significantly influenced the height of the scions at the stage of two leaf-umbrellas, without significant impact on the survival rate, sprouting rate, withering rate, nursery release rate, or scion stem thickness. The interaction between grafting time and topping time did not significantly affect the survival rate, sprouting rate, withering rate, growth volume, and nursery release rate of the grafted seedlings. It is advisable to adopt a strategy of overwintering with the stalks for mini-rubber seedlings grafted in winter, and to perform topping from February to March after the beginning of spring in the next year, which could significantly shorten the time of budding, reduce the number of times the rootstock debudding, and ensure higher scion growth quality, and this timing aligned well with the planting period of the year, offering significant practical value for production. For seedlings with rootstocks that have reached two leaf-umbrellas, topping just above the first pair of true leaves did not affect the survival rate and could control the withering rate below 4%, demonstrating good technical stability. It is recommended that in practical production, the grafting and topping times for rubber tree seedlings should be strictly controlled to ensure the rootstock reaching an appropriate growth state before topping, and management measures should be adjusted as needed to achieve the best nursery results. The application of the findings would help improve the production efficiency of rubber tree seedling cultivation.