The paper aims to provide a high-efficiency, high-quality and low-cost machining method for lithium tantalite (LT). A fixed abrasive pad with 3000# diamond abrasive, resin bonder, and compounded with auxiliary material was manufactured through mixing, curing, compaction, trimming, etc. The material removal rate (MRR), surface morphology and roughness (Sa) were chosen as indicators to evaluate the processing performance of LT wafer machined with free abrasive and fixed abrasive pad, and compare the processing results of free abrasive with fixed abrasive pad under the same test condition. At 40 kPa and 140 rad/min, the Y-36° LT wafer was lapped with 3000# free abrasive pad. 10 minutes later, the MRR of the LT was 37.89 μm/h and the surface roughness Sa was decreased from 420 nm to 233.308 nm. There were deep scratches on the surface and they were likely to cause wafer breaking. Small amount of abrasive grains embedded on the LT wafer after machining can be observed. Under the same conditions, the LT wafer was also lapped with the fixed abrasive pad. 10 minutes later, the MRR of the LT was 66.19 μm/h and the surface roughness Sa was decreased to 97.004 nm, shallow scratches can be observed on the wafer surface, and none abrasive particle were embedded on the surface of LT wafer. Compared with the result from the free abrasive lapping, the test using the fixed abrasive pad has better surface morphology, higher material removal rate and better finishing efficiency. When the LT wafer is lapped with fixed abrasive pad, the surface roughness of LT wafer decreases with the increase of pressure and speed; while the MRR increases with the increase of pressure and speed.