Flavera bidentis (L.) Kuntza is an alien weed with a strong ability to invade. The successful invasion by this weed might be related to its ability to readily adjust to the environment. A laboratory study of the physical characteristics of Flavera bidentis and the effect of environmental factors on its seed germination and seedling growth was conducted to determine the factors that enable it to rapidly invade new environments. The results showed that a single plant can produce more than ten thousand seeds and the seeds are very small. This accounted for its ability to rapidly invade new areas. Temperature, light, and seed burial depth were the key factors affecting seed germination. Seeds germinated at a constant temperature of 5 to 40℃ with optimum seed germination at 25℃ and optimum seedling growth at 25-35℃. Seed germination was light sensitive. Maximum germination (74.44%) occurred when seeds were planted on the soil surface. No seedlings emerged when planted at a depth of 3 cm. The effect of pH on seed germination was not significant, but the seedlings grew better under acidic conditions than in alkaline soils. The seed could endure NaCl stress and drought stress to some extent, but root length and seedling length became shorter when the stress became severe. A soil water content of 50% was the best condition for the seed germination and seedling growth.