The control of fusion splicing energy and heating time is a key to avoid air-hole shrinkage in fusion splicing process for photonic crystal fibers (PCFs). A mathematic model of mechanics characteristic in fusion splicing process for PCFs is developed from classical mechanics theory. Furthermore,the distortion of air-hole and fusion splicing loss are analyzed. Experiments and analysis show that distortion of air-hole may be controlled by adjusting fusion splicing energy and heating time. According to theory analysis results,fusion splicing experiment is carried out. The experiment result shows a good consistency with the analyses result.