Abstract: Several factors, which influence beam qualities during relativistic intense electron beams transportation, have been analyzed systematically in this report. Aimed at the principal contradictions manifested in the different energy areas of beam, corresponding measurements are adopted to restrain the harmful effects of space charge, fluctuation of transporting magnetic fields, corkscrew motion or BBU instability respectively. All the measurements can be summed up in choice of appropriate radius of beam and matched transport magnetic field on the design of beam transport system. The principal strategy of transport field arrangement is presented, and the overall arrangements of beam transport system of “SL-I” LIA are described.