The influence of temperature fluctuation upon focal length, harmonic wavelength and diffraction efficiency of harmonic diffractive lenses was analyzed, correspondingly, the mathematic formulas were constructed and some numerical simulations were carried out. The shifting function, which denoted the degrees of focal length and harmonic wavelength varied with temperature fluctuation, was developed. The disciplinarians of harmonic diffractive lenses’ diffraction efficiency varying with temperature were listed. In the end, the influence of temperature fluctuation on harmonic diffractive lenses with different phase-matching number and the same designed wavelength was compared. The result indicates that the diffractive lens with lager phase-matching number was more sensitive to temperature fluctuation.