The main components of urinary crystallites in patients with CaOx stones were calcium oxalate monohydrate (COM), uric acid (UA), calcium oxalate dihydrate (COD) and calcium phosphate (CaP), which were similar to the components of stones (COM, COD, UA, and CaP).[Conclusions] The formation of CaOx stone was related to the presence of COM, UA, and CaP crystals in urine. UA and CaP crystals could induce the development of CaOx stones by heterogeneous nucleation. The formation mechanism and the influential factors of CaOx stones were discussed on the basis of the components of urinary crystallites.