A program TRANSPORT has been used to calculate and analyze the ion optical characteristics of the cyclotron beam transport system in Sichuan University. The results show that: i) the calculations agree with the performance in practice under the parameters operated now in this cyclotron; ii) if the geometry parameters are changed the field parameters will be adjusted moderately

the size of beam envelope in all lines will be decreased

the beam intensity reached the targets will be increased and the beam spot property on the targets will be better.