Abstract: In order to realize the high resolution, wide temperature range working environment demand, low-cost and strong environmental adaptability of photoelectric detection system, a thermalization optical system is designed with high resolution based on sphere lens beyond normal temperature. The transmission optical configuration is chosen. The wide temperature range athermalization design is realized based on all sphere optical parts and aluminum mechanical parts.Prototype design results show that the optical system operating band is 0.486~0.656 μm, focal length is 100 mm, F number is 3.0, field size is 5.85°×5.85°. The visible detector chooses a high resolution 4 096×4 096 pixel detector with pixel size of 2.5 μm×2.5 μm, at 200 lp/mm, axis view of the modulation transfer function (MTF) is not less than 0.38, other field of the off-axis modulation transfer function (MTF) is not less than 0.35, the system distortion is less than 0.55%, In the temperature range of -110~+120 ℃ the system has good image effect.The optical system has compact space, high resolution, good processing technology, esay to adjustment, low cost, strong environmental adaptability and other technical characteristics.The performance indexes meet the application specifications.It is widely applicable in optical detection guidance, unmanned monitoring, defect inspection, and petroleum exploration under extreme temperature.