The term “molecular chaperone" was originally used to describe a class of biomolecules, which mediate interactions between nuclear acids and proteins in the nucleus. Nucleoplasmin is the first identified nuclear chaperone, existing in a form of pentamer in vivo , and participates in several important cellular activities such as nucleosome assembly, sperm chromatin remodeling and apoptosisrelated chromatin condensation. Nucleoplasmin has abundant acidic amino acids, forming acidic tracts as essential functional domains. These acidic tracts shield the positive charge of histones, delivering histones to negatively charged DNA step by step, so as to avoid charge-driven aggregation under physiological ionic strength and facilitate an ordered assembly of nucleosome. In addition, determination of crystal structure of nucleoplasmin has driven the study into further discussion of molecular mechanism and establishment of model between nucleoplasmin and DNA. In this review, we mainly focus on the progresses in the structure and biological properties, the related functions as well as activity regulation of nucleoplasmin.