We investigate the topological characteristics of complex networks as exemplified by the urban public traffic network (UPTN) in Chinese top-ten biggest cities. It is found that the UPTNs have small world behaviour,by the examination of their topological parameters. The quantitative analysis of the transport efficiency of the UPTNs reveals their higher local efficiency El and lower global efficiency Eg, which coincide well with the status quo of those Chinese cities still at their developing stage. Furthermore, the topological properties of efficiency in the UPTNs are also examined, and the findings indicate that, on the one hand, the UPTNs show robustness to random attacks and frangibility to malicious attacks on a global scale; on the other hand, the interrelation between UPTN efficiency and network motifs deserves our attention. The motifs which interrelate the UPTN efficiency are always triangular-formed pattes, e.g. motifs ID 238, ID 174 and ID 102, etc.