The present invention provides apparatus for self-phase modulation noise calculation, apparatus for self-phase modulation noise elimination and optical coherent receiver. The apparatus for calculation comprises: a signal receiver to receive an input signal; a calculator connected to the signal receiver to calculate a self-phase modulation noise at the current instant by using the signal powers of an input signal waveform at the current instant and at several sampling instants adjacent to the current instant. The embodiments of the present invention calculates the self-phase modulation noise at a certain instant by using the signal powers at a plurality of digital sampling periods before and after this instant, and when the apparatus is used to calculate the self-phase modulation noise of each of the sub-spans in an optical fiber transmission link, in case that the calculation precision is ensured, the granularity of the sub-spans may be reduced, thereby lowering the complexity of the calculation.