Abstract: The analyses of composition of urinary calculi can provide significant on the clinical diagnosis and treatment reference to the cause of lithiasis and the prevention of recurrence. Fourier infrared spectrophotometry is an ideal analytical means for the determination of the composition of urinary calculi. The internal standard method, absorbance ratio method and first-derivative spectroscopy method adopted in the quantitative analysis of calcium oxalate phase in urinary calculi by using fourier infrared spectrophotometry apparatus were compared. Calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) in mixed calculi were easily quantitative determined by this analytical method. And the result of analysis could preliminarily meet the demands of urinary calculi.