容错技术是计算可靠性的重要保证，实现容错的途径是冗余，而重构是容错计算机系统动态冗余技术的重要环节．本文以我们自行研制的航天容错计算机ＦＴ—ＨＩＴ系统为背景，论述ＴＭＲ计算机系统的降级重构和升级重构技术． Fault-tolerant technology is an important guarantee for computing reliability. The way to achieve fault tolerance is redundancy, and reconfiguration is an important part of fault-tolerant computer system’s dynamic redundancy technology. In this paper, our self-developed space-fault tolerant computer FT-HIT system as the background, discusses the TMR computer system degradation and reconstruction and upgrade reconstruction techniques.