The embodiment of the invention discloses a route method, wireless sensor nodes and a system of a wireless sensor network and relates to the field of computer network. The method includes the steps of: with a plurality of routes existing among wireless sensor nodes, respectively calculating the weight value of each route according to route parameters selected by each route, obtaining the transmission requirement of data to be transmitted, selecting data parameters according to the data transmission requirement and calculating the weight value of the present data to be transmitted according to the data parameters; selecting one of the route weight values to match with the data weight value and taking the route corresponding to the route weight value as a route for transmitting the present data to be transmitted. The wireless sensor node includes a route weight calculation module, a data weight calculation module and a route selection module. The invention also provides a route system of the wireless sensor network. The embodiment can transmit the present data to be transmitted on a route matching with the data transmission requirement, thus realizing load balance.