1. A wireless network device comprising: and a memory configured to store routing latency information for routing to other nodes in a network; a processor configured to determine transmission latency requirement of transmitting data packets to a destination node according to transmission latency requirement information carried in the data packets after obtaining the data packets to be transmitted, query available routes to the destination node, and the stored latency information corresponding to the available routes, and select a route most approximate to the determined transmission latency requirement from the available routes according to a query result of the query module, and transmit the data packets, wherein the memory is further configured to transmit a predetermined amount of test packets to other nodes in the network for obtaining transmission latencies of the test packets in respective routes, calculate respectively transmission latency averages of the test packets in the respective routes and save the transmission latency averages as the routing latency information, and calculate respectively transmission latency variances of the test data packets in the respective routes and save the transmission latency variances as the routing latency information, and wherein the processor is further configured to calculate difference values between the transmission latency requirement and the transmission latency averages in the respective available routes, select the available route with the minimal absolute difference value, and select preferentially the available route with the minimum transmission latency variance in case that the absolute difference values corresponding to multiple available routes are equal.