Functions often depend on the assembling of macromolecules into well-defined networks and complexes. Our research is to use recombinant collagen triple helix as a model system to explore the determining factors that govern the higher level molecular assembly. About twenty different types of collagen molecules have been identified in humans, occurring in almost every tissue. Different types of collagen share the same basic structure unit – the triple helix, consisting of three poly-peptide chains with the characteristic (Gly-X-Y)n repeating (amino acid) sequence. The triple helix further assembles into different supramolecular structures that confer the diverse biological properties of different tissues. Understanding of the mechanism of molecular assembly of collagen will be essential for our understanding of the molecular basis of tissue functions, the mechanism of macromolecular organizations and how mutations in collagens cause diseases.