In view of traditional zoom lens cannot consistently and clearly image during the whole zoom process when the ambient temperature is changed, which needs to focus frequently at middle focal length position. This paper proposes a new design method which is named optical passive half-athermalization zoom lens design, and an optical passive half-athermalization zoom lens is designed by this novel method. The focal length of zoom lens is 30-1000 mm, spectrum wavelength is 486-656 nm, and F-number is F_4.4-F₈. Most importantly, the shortest focal length position of zoom lens is optical passive athermalization. The optical system has compact structure and excellent imaging quality, and based on method of passive half-athermalization design, optical system at any temperature between -40 ℃ and +60 ℃, which only need to focus once at the longest focal length position of zoom lens, that can ensure consistently and clearly image during the whole zoom process. There is no need to focus frequently in any middle zoom position, and the temperature adjustment of zoom lens is only -0.56-+0.82 mm, which have verified method of optical passive half-athermalization zoom lens design correctly. According to this method, zoom lens not only overcomes trouble of frequently focusing in traditional zoom lens, but also greatly reduces amount of temperature focusing and benefits on fast focusing.