On the photon counter data observed with Photoeleetric Transit Instrument of Beijing Astronomical Observatory during the period from 1988 to 1990, corrections of right ascensions of 324 stars are given. The mean precision (<m_{DELTA}{alpha}cos{delta}_>) is 4.7ms. The mean observational epoch is 1989.7. The relations of residuals with magnitudes and spectral types are discussed and given respectively. Finally the systematic corrections (PPCP4-FK4) are also analysed.