The invention relates to a maslinic acid derivative as well as a preparation method and an application thereof, belonging to the technical fields of medicines as well as preparation methods and applications thereof. The maslinic acid derivative has the structure shown as the right structural formula. In the formula, X is S, CH or CH=N; when the X is the S, Y=C, R=NH2; when the X is the CH, Y=N, R= formula as the lower right; when the X is the CH=N, Y=C, R=H, CH3, OH, SH, NH2, SCH3 and NHCH3. Natural product oleanolic acid is used as a raw material and oxidized to obtain a corresponding 3-carbonyl derivative, the corresponding 3-carbonyl derivative is halogenated or formylated or forms enamine in the C2-position and finally the corresponding C2-position and C3-position heterocycle maslinic acid derivative is obtained by a series of condensation reaction. The maslinic acid derivative can be used as an insulin sensitivity increasing agent. The serial and novel maslinic acid derivative is efficiently compounded by introducing serial heterocycles in the C2-position and the C3-position of the natural product maslinic acid, a compounding method is simple, and the PTP1B inhibition activity of the compound is obviously strengthened by the structural reformation of the part.