Signal reconstruction is an important step in communication between the computer controlled system and computer system. Based on the famous Shannon reconstructing theory, some classical algorithms (such as ZOH algorithm and 1-order reconstruction algorithm, etc.) were analyzed and some shortages of these algorithms were pointed out. And, a new practical 1-step fault-tolerant prediction algorithm was set up. In order to realize this fault-tolerant algorithm, the three-points-interpolation algorithm was combined into the reconstruction process. This new algorithm has the ability to overcome bad influence from outliers and has very simple computing complexity. So, this algorithm can be safely used in on-line control.