This paper studies the dynamic relationship between users’ participation and creative output of new product from the user perspective. Based on the theoretical analysis, this paper explores how users’ participation changes in the different stages of creative output. The hypotheses have been empirically tested by using 2400 users from 12 firm-hosted innovation communities. The results show that both breadth and depth of users’ participation increase accompanying with improvement of creative output quantity; similarly, the depth of users’ participation increases accompanying with improvement of creative output quality while the breadth of users’ participation only increases in part stages of creative output quality. The results may provide some advice for enterprises to take dynamic measures to encourage users to participate in the product innovation.