Abstract: Cryo-scanning electron microscopy (Cryo-SEM) is a powerful tool in the life science research because of its advantages such as observing aqueous samples under high vacuum condition, high resolution, simple and rapid sample preparation, fracture etching of samples, etc. Through the surface morphology observation of biological samples using Cryo-SEM's freeze fracture method, both the surface structural information and the internal structural information of the samples can be observed. The plant samples from the upper and middle assimilated branches of Haloxylon Ammodendron and the liquid samples of whey protein fiber (WPIF) were taken as the experimental materials, and the samples were subjected to a freeze fracture treatment to observe and compared the structures of the samples before and after the freeze fracture treatment. The results showed that the chloroplasts of plant cells and the fine hairs between the cells could be observed under the test conditions of a sublimation temperature of −100 ℃, a sublimation time of 10 min, a cold platform temperature of −175 ℃, and an observation voltage of 5 kV. And the lamellar structure of medium chain triglyceride and protein fiber can be observed under the test conditions of a sublimation temperature of −100 ℃, a sublimation time of 5 min, a cold stand temperature of −175 ℃, and observation voltage of 5 kV after freeze fracture of WPIF. However, the above results could not be observed for the samples without a frozen fracture treatment.