The network coding (NC) could improve the throughput and reliability. However, it is vulnerable for the pollution attack and the eavesdropping attack. What's more, due to the high complexity of traditional secure network coding (SNC) schemes, many of them are not suitable for resource-constrained wireless sensor network (WSN). In this paper, a low complexity secure network coding based on double primes (DP-SNC) is proposed to defense against the eavesdropping attack. In DP-SNC, DP-sequence is first constructed by double primes operation and randomized transform, and then the encoding process is divided into two phases: source node information is scrambled by using pseudo-random characteristic of DP-sequence, and fragmented data packets are formed; via the mapping function constructed Vandermonde code by using the first non-zero value in initial value of DP-sequence, these data packets are re-encoded and transmitted. The simulation results show that this scheme could guarantee the security of the original information, defense global eavesdropper; and lower computational complexity, smaller encryption capacity and lower space overhead.