The invention provides an opportunity-type data transmission method based on multiple behavior sites, aiming to solve the problem of incapability of accurately sending data to attribute users of the behavior sites. According to the method, the user performs site behavior registration on a cloud server, the cloud server stores a user/behavior site combined matrix, and a server updates the matrix timely and returns a newest time slice vector to the user. A source user starts a data forwarding process after applying data from the cloud server. In the process of data forwarding, a circuit is initiated and messages are transmitted to the attribute users of h different behavior sites, wherein the h refers to the number of the sites. In the progressive gradient increase stage of forwarding, the messages are forwarded to intention receivers of the behavior sites layer by layer. The data are sent to the intention receivers of all the surrounding behavior sites in a multicast mode. The data are forwarded to the users of the behavior sites by taking user behavior attribute weights as forwarding conditions, so that data transmission rate is improved effectively and energy consumption is lowered.