The 60 MeV Proton Radiation Effects Facility (PREF) spent nearly 1 month at the commissioning phase, during which the multi-strip ionization chamber (MIC) at the experimental terminal offered the core parameters, beam spot, scanning area, scanning uniformity, beam flux. However, the projection distribution provided by the MIC loses some information, such as the flux and the uniformity in a selected area less than the scanning area. This paper used a method of two-dimensional reconstruction to provide a 2D uniformity of selected area. Revealing the trace of the pencil beam at a sampling rate of 10 kHz.