Abstract: The working theory and optical criterion for the CD optical system is introduced,then some main issues for the design and assembling are discussed.A kind of CD lens for practical use and mass production have been designed.Based on the calculation of the lens,the optical performance curves affected by the LD astigmatism,manufacturing errors and system errors are presented.The design can endure various manufacture errors.Even the focusing error and disk tilt occur,excellent optical performance can be obtained within the whole tracking area,which shows the design is practical.