Problem statement: Secure data aggregation is a challenging task in wireless sensor network due to the facts like more complexity, greater overhead in the case of cryptographic techniques. These issues need to be overcome using efficient technique. Approach: We propose a fuzzy based secure data aggregation technique which was having 3 phases. In its first phase, it performs clustering and cluster head election process. In the second phase, within each clusters, power consumed, distance and trust values were calculated for each member. In the third phase, based on these parameters, fuzzy logic technique was used to select the secure and non-faulty node members for data aggregation. Finally, the aggregated data from the cluster heads was transmitted to the sink. Results: By simulation results we show that our technique had improved throughput and packet delivery ratio with reduced packet drop and less energy consumption. Conclusion: The proposed technique efficiently checks for malicious nodes based on the system parameters and maintains a secure aggregation process in the network.