Because of the harsh environment of operating conditions of marine nuclear power plant, some parameters was often lost due to failures of measuring instrument and measurement of transmission channel, which influenced the operator’s judgement about the running states of the system and further jeopardize the operation safety of the system. Therefore, this paper put forward a reconstruction method based on multisignal coupling. This method reconstructed the lost signals with a reconstruction data model designed according to the strong coupling of important parameter and the running historical data of nuclear power plant by the method of artificial intelligence and data statistics. Tests show that this method can reconstruct the lost signal fast and efficiently in normal operation transient conditions of nuclear power plant, and is fit for being used online.