The computational fourier-transform moire (CFTM) method has been briefly explained and this method was used to perform strain analysis of a misfit dislocation in a strained Si/Si_0.55Ge_0.45 layer. An essential advantage of the CFTM method is that it does not require unwrapping, such that errors due to improper unwrapping can be excluded. The analysis results revealed that the Si layer was grown with tensile stress on Si_0.55Ge_0.45 and lattice constant of the Si layer along the growth direction was 1.9% smaller than that of Si_0.55Ge_0.45. On the other hand, strain of the misfit dislocation in the strained Si/Si_0.55Ge_0.45 layer was maximum at the dislocation core due to an extra half-plane and the e_xx and e_yy values were positive and negative, respectively, along the direction of a burgers vector.