A solution of partition detection based on aspheric cylindrical lens array is proposed, which aims at the requirements of circumferential detection system on the detection laser beam divergence angle and energy distribution. Source of the detection system is a fast-axis collimated laser diode array. Slow-axis light power is distributed via aspheric cylindrical lens array. Collimated line source approximation is put forward to simplify the complicated process of corresponding calculation on Gaussian beam, and an equation of the aspheric curve is finally established. The aspheric cylindrical lens array is determined by applying this equation, the system can obtain outgoing beam with adjustable divergence angle and uniform power density distribution about plane angle in sagittal plane. And the evenness can reach 98.64%. A lens array with wavy structure is designed to diminish the effect of tolerance of optical system. According to tolerance analysis, the refractive index tolerance of lens material only influences the beam divergence angle instead of the evenness of light distribution. And the traditional structure of lens array is replaced by wavy structure so that wedge shape between adjacent lens can be eliminated effectively, which reduces the difficulty and tolerance in manufacture. Moreover, the length of line source is consistent with the periods of lens array, which weakens the influences of tolerance of lens eccentricity and lens tilt during fabrication.