  A beam line is built after the IHEP RFQ for halo study. To determine
transverse emittance and ellipse parameters of the RFQ output beam, beam size
data obtained from the first two of 14 wire scanners are employed. By using the
transfer matrix method and the least square method, a set of linear equations
were set up and solved. The solutions were then applied as initial beam
parameters in multi-particle simulations to check the method of calculation. It
is shown that difference between the simulated RMS beam size and the measured
one at the measurement location is less than 7%, which is acceptable in our
experiments.
