Abstract:A combined formula of international terrestrial reference frame (ITRF) is deduced when new local tie vectors are introduced. This paper analyses the effects of new local tie vectors on coordinates and their velocities of ITRF2008. Solved results are compared with ITRF2008 when introducing Changchun, Kunming, and Urumqi local tie vectors and their variance-covariance matrices from the 2011 ITRF2008 crustal movement observation network of China (CMONOC). The results show that coordinate differences for the most of sites are within 10 mm, and velocity differences are less than 1 mm/a. Moreover, the horizontal velocity and vertical velocity fields of the most sites are consistent with ITRF2008 velocity fields.