Innovation is the key to the success of an enterprise. The innovation in products can make enterprises more competitive. The product function is the essential part in consumers’ demand for products. As a new trend of innovation in products, function integration plays an increasingly prominent role in the innovation design of products. Based on the essence of the innovation design--market demand, this paper analyzes the status and practical application of function integration in product innovative design, especially in the design of home appliances. The design trend of function integration in home appliances is also summarized. In the end, function integration is applied to the innovation design of heater practically, which is more humanistic and closer relationship between people and products.