In multi channel highspeed parallel sampling systems, error estimation and error correction (equivalent to signal reconstruction) are the most important aspects.The paper proposes a cubic spline interpolation method with sampling time and sampling waveform to reconstruct the multichannel nonuniform sampling signal. In the coefficient of the function, the periodicity of the multichannel timebase error is used to simplify the operation and reduce the Computational complexity, and is suitable for sampling of any number of channels. The simulation results show that the proposed method can reconstruct the multichannel highspeed parallel sampling signal effectively and the correction effect is good.