Abstract: 1,3-Bis(2/-tetrahydrofuryl)-5-fluorouracil, C₁₂H₁₅FN₃O₄, crystals are triclinic system, a = 8.911(4)A, 6 = 11.744(5 ) Å, c = 12.320( 7 ) Å, α = 99.69(4)°, β = 93.49(4)°, γ = 97.83(4)°. Space group P1, Z = 4. The diffraction data (Cu K_a) were collected with NICOLET R₃ four-circle diffractometer. The structure was determined by SHELXTLdirect methods and refined by the least-square program, R= 0.089.Comparing this structure with FT-207, we find that the structure features of their 5-fluorouracil rings are all the same as the one of 5-Fu. One more tetrahydrofuranose ring in FT-207 and two more these rings in FD-1 than 5-Fu make their structures quite different. They all are chemical anticancer drug, but FD-1 is the best one. Its curative effect is 1.7 times as much as of FT-207, and its toxicity is only 1/2 - 1/3 that of FT-207. The determination of crystal structure of FD-1 is helpful for revealing it's anticancer mechanism.