A Schiff base rich in sulfonic acid group and carboxyl group was prepared by glyoxalic acid and 2-Amino-1,4-benzenedisulfonic acid and was treated as pickling auxiliary used in pickling process，swelling rate of acidic pelts, shrinking temperature of wet-blue leather, the content of Cr2O3 and of spent tanned liquor has been determined. Result shows: 2％ pickling auxiliary（based on limed pelts weight, same below） was used in salt-free pickling, swelling degree of pelts pickled was about 4％, on this basis, 1％ sodium chloride was added into pickling liquor, swelling phenomenon of pelts pickled was avoided. 4.5％ chrome powder was applied to less-salt pickling chrome tanning, Ts of wet-blue leather could achieve to 105.5℃. Compared with traditional pickling chrome tanning process, the content of Cr2O3 and Cl- of spent tanned liquor significant were reduced from 3.305g/L和374.2mmol/L to 1.546g/L and 59.6mmol/L. Observation from ESEM showed that fiber uniformly dispersed, surface smooth, pores clear, and EDS showed chromium elements was uniformly distributed in cross section of pelts. Compared with traditional process, tensile strength, elongation at break and tear strength were up to 32.8MPa, 56.8％ and 80.2N/mm respectively.