Abstract: The present invention relates to the field of pharmaceutical chemistry, and specifically to a method for preparing cholesterol, a derivative thereof, and an analog thereof. The derivative of cholesterol comprises, but is not limited to, 7-dehydrocholesterol, 25-hydroxycholesterol, 25-hydroxy-7-dehydrocholesterol, and ergosterol. In the present invention, a compound represented by formula I can be prepared by means of a microbial transformation using phytosterols as a raw material, followed by preparing cholesterol, the derivative thereof, and the analog thereof.