Abstract: With the rapid development of communication and computer networks，more and more network equipments and applications require synchronized time.But the end systems time synchronization has not been satisfactorily resolved.In this paper，first systematically proposes the mathematics model of the end system clock’s dynamic.A Subsection Filtration Time Synchronization algorithm（SFTS） is proposed.The SFTS contains there parts：server initiative time synchronization algorithm，interval time compensation for clock skew，and queue filtration and frequency saltation filtration.Finally，SFTS in a test network and contrasted it is validated with the NTP.The experiment result demonstrates that SFTS can really achieve a high precision synchronized time between multiple computers.

Key words: time synchronization, clock synchronization, clock skew, error filtration

摘要： 随着通信及计算机网络的发展，越来越多的网络设备和网络应用对同步时间提出了越来越高的要求。但迄今为止端系统间的时间同步并没有得到很好的解决。首先系统描述了端系统时钟动态性的数学模型，然后提出了一种基于分段过滤的时间同步算法（SFTS算法）。该算法包含服务器主动式时钟同步算法，基于分段估算的频率差补偿算法，排队与频率跳变过滤算法三个部分。最后在实验网上对该算法进行了验证，并与NTP协议进行了对比。实验结果表明该算法确实能够实现大规模计算机间的高精度时间同步。

关键词: 时间同步, 时钟同步, 频率差补偿, 误差过滤