A rectification method was developed for the purification of pivalic acid (PVA) on an experimental scale. Ultrapure PVA with a purity of 99.993% was prepared at a rate of 250mL a week by multistep rectifications, a more convenient and much faster method than the traditional zone refining method. Typical operational conditions were: head pressure around 1kPa, reboiler temperature 85 degrees C, head vapor temperature 55 degrees C, condenser temperature 36.5 degrees C, and reflux ratio of 6:1. A formula was given to determine the purity of PVA based on the relationship of freezing point and purity. The freezing point of ultrapure PVA, which was obtained by measuring solidification temperature curve using an inner sheath method, is 35.912 +/- 0.001 degrees C.