The invention discloses a process method which adopts sulfated waste velveteen to produce microcrystalline, mainly including the following steps: measuring and detecting, quantitative neutralization, bleaching, washing, drying, crashing and sieving. The process method is characterized in that in the measuring and detecting process, first, the proportion of alkali used to neutralize sulfated wastevelveteen is detected, then alkali solution is prepared according to the proportion and quantitative sulfated waste velveteen is added for quantitative neutralization, and finally the bleaching process is carried out. Compared with the prior art, the process method requires less energy to process the sulfated waste velveteen; particularly, the proportioning measurement is adopted to determine theamount of waste velveteen and alkali, which reduces the amount of used alkali to the minimum while sufficiently ensuring the quality of the microcrystalline cellulose and greatly reducing production cost. The discharge liquid is neutral or approximately neutral and has little pollution to the environment. On the other hand, the water amount used during neutralization is small, the total dischargeliquid is small in amount and is easy to be disposed without pollution, and the cost is also greatly reduced.