Abstract: The cytstal growth of proteins and other biomacromolecules is an important study in space science'Using tube-like vapour diffusion apparatus made in China,two missions of protein crystallization have been carried out on Chinese re-entry satellites.52% and 80% of 48 samples prepared by 10 different kinds of proteins yielded crystals in the two space experiments respectively,and among them,a few of the proteins preduced better-quality Crystals.The results of the two missions show that the microgravity environment in space benefits improvement of protein crystal growth, and in the case with good enough optimized crystallization conditions,the space-grown protein crystals have larger size,better morphology and higher intend order than the Earth-grown crystals of the same protein.The effect of microgravity on protein crystal growth and its exploitation are also discussed in the paper.