The tilt relation and lattice misfit phenomenon between MBE-HgCdTe layers and different substrates were studied by employing reciprocal lattice mappings technology. The precise fit zinc composition in Cd 1-yZn yTe substrates was determined by analyzing the elastic deformation in MBE-HgCdTe layers. The result shows that MBE-HgCdTe epitaxial layers and substrates are tilted with respect to each other, and the tilt angle increases with the lattice mismatch. In the case of little mismatch between substrate and layer, the layer is strained with partially relaxation of stress. While the layer is full relaxed, the lattice mismatch becomes large. In this case, the HgCdTe layers have more misfit dislocations and larger width of half maximum.