This paper educes the expressions between the numbers of pairs, links with more than two pairs, inner pairs and outer pairs in the Assur Group, extends the theory about Assur Group and lists 2,4,6 and 8 links Assur Group eigenvalues. Based on these, a new topology drawing method is addressed, with this method can get many different Assur Group Models with same eigenvalue. Then Model Array is addressed to realize the Assur Group numeric expressing. The above research provides a new method for mechanism model synthesis based on Assur Group, Assur Group eigenvalue can also be used to identity and creative design mechanism, an example is listed to validate its rationality.