Preparation process of white ultra-soft environment-friendly leather

The invention discloses a preparation process of white ultra-soft environment-friendly leather. According to the process, leather having been subjected to fleshing, water squeezing, shaving and weighing treatment is sequentially subjected to five steps including acid pickling, neutralization, retanning, retanning neutralization and dyeing. During acid pickling, formic acid and oxalic acid are usedfor adjusting a pH value, pickling is conducted, standing overnight is conducted after pickling, and subsequent operation is carried out on the next day; in the process of retanning, a chrome-free tanning agent is adopted to replace a chrome tanning agent, a process sequence is properly adjusted, leather properties are adjusted by utilizing the combination of different reagents; and in the processes of neutralization and retanning neutralization, neutralization is conducted twice in each process to realizing filling and fat addition step by step in multiple times, so the ultra-soft leather property is obtained, and t