In many time synchronization protocols of wireless sensor networks（ WSNs）

accuracy

high efficiency and simplicity of the algorithm always be given priority. Besides

fault-tolerant time synchronization algorithm is also paid more attention. In view of classical algorithm floating time synchronization protocol（ FTSP）

it comprehensively considerates the energy consumption

synchronization precision

scalability and and other aspects that may be requested. propose a fault-tolerant time synchronization algorithm that based on FTSP

the algorithm calculate new clock drift rate through measured historical finite clock drift rate weighted average. The weighting coefficienty is dynamically determined according to variance of historical measurements value. Finally

simulation analysis is carried out on clock drift rate of new algorithm and change of error message received clock drift rate by Matalab. The results show that the improved algorithm has strong fault tolerance.