The invention relates to a rice seed cold-resistant germination-promoting seedling-strengthening agent and a use method thereof, and belongs to the technical field of crop cultivation, quick lime (with the content >= 95%), a Bacillus subtilis commodity strain (10 billion live Bacillus bacteria / gWP), plant ash powder and ginkgo leaf or ginkgo fruit peel extract are mixed according to the mass ratio of 80-150:1.0-2.5:100-200:5-15, clean water is added to completely dissolve the mixture into a 1%-3% water solution, rice seeds are soaked in the water solution for 45-60 minutes for accelerating germination in accordance with the seed-soaking germination-accelerating technology in the prior art; when in seeding, the 1%-3% water solution is prepared according to the mass ratio, the 1%-3% water solution is uniformly poured onto the surface of pieces of a water cultivation seedling field or a seedbed of dry land seedling cultivation, or uniformly applied and mixed into seedling throwing plate nutrient soil, or applied to the surface of pieces of a direct sowing paddy field, and then seeding is performed. The rice seed cold-resistant germination-promoting seedling-strengthening agent can effectively solve the problems that rice seeds are slow to sprout and germinate, and not irregular to germinate, seedlings are weak, seedlings are susceptible to diseases, and the like, and can improve germination rate, seedling-forming rate and seedling rate of the rice seeds and strong seedling rate.