All INT2 sessions from 2002 to 2009 are calculated in this paper, the UT1 corrections calculated by the observations and the periodical change rules of its formal deviation are analyzed with Jurkevich and Fourier methods, and several cases about the corresponding radio source sky-coverage of INT2 sessions are pointed out. According to the results, the atmospheric excitation in summer probably influence the UT1 estimation about 1.5s, and effective radio source sky-coverage can make up for the defects of few observation scan. (2014) Trans Tech Publications, Switzerland.