The invention discloses oxoindolespiro tetrahydrofuran fluoride and a preparation method thereof. The structural formula of oxoindolespiro tetrahydrofuran fluoride is shown as formula I. The inventionfurther discloses a crystal form of a compound shown as the formula I, the crystal form is a monoclinic system, cell parameters include that a=9.09964(19) angstrom, b=9.3177(3) angstrom, c=15.6040(4)angstrom, alpha is equal to 90 degrees, beta is equal to 99.228 (2) degrees, and gamma is equal to 90 degrees; space group is P21, Z=2, and cell volume is 1305.91(6) angstrom<3>. The invention further discloses a preparation method of the crystal form, the compound or the crystal form thereof or a solvate thereof or application of pharmaceutically acceptable salt thereof in preparing antitumor drug.