A fatty acid compound or a pharmaceutically acceptable salt thereof, wherein the said fatty acid compound has the structure of formula II: wherein R 1 and R 2 are each independently H, Cl alkyl or phenyl; R 3, R 4, R 5 and R 6 are each independently C1∼C4 alkyl or phenyl; alternatively, R 5 and R 6 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atom form a C3∼C7 cycloalkenyl group, alternatively, R 3 and R 4 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group; m, n are each independently 1, 2, 3, 4, 5 or 6, the double bond is either cis or trans; or wherein said fatty acid compound has the structure of formula III: wherein, R 3, R 4, R 5, R 6 are each independently H, C1∼C4 alkyl, C1∼C4 alkenyl, alkynyl, C3∼C7 cycloalkyl, C3∼C7 cycloalkenyl, phenyl or benzyl, alternatively, R 5 and R 6 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group, alternatively, R 3 and R 4 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group, m, n are each independently 1, 2, 3, 4, 5 or 6; or wherein said fatty acid compound has the structure of formula IV: wherein, R 3, R 4, R 5, R 6 are each independently H, alkyl, C1~C4 alkenyl, alkynyl, C3∼C7 cycloalkyl, C3∼C7 cycloalkenyl, phenyl or benzyl, alternatively, R 5 and R 6 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group, alternatively, R 3 and R 4 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group. m, n are each independently 1, 2, 3, 4, 5 or 6, p is 1, 2 or 3. wherein R 1 and R 2 are each independently H, Cl alkyl or phenyl; R 3, R 4, R 5 and R 6 are each independently C1∼C4 alkyl or phenyl; alternatively, R 5 and R 6 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atom form a C3∼C7 cycloalkenyl group, alternatively, R 3 and R 4 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group; m, n are each independently 1, 2, 3, 4, 5 or 6, the double bond is either cis or trans; wherein, R 3, R 4, R 5, R 6 are each independently H, C1∼C4 alkyl, C1∼C4 alkenyl, alkynyl, C3∼C7 cycloalkyl, C3∼C7 cycloalkenyl, phenyl or benzyl, alternatively, R 5 and R 6 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group, alternatively, R 3 and R 4 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group, m, n are each independently 1, 2, 3, 4, 5 or 6; or wherein said fatty acid compound has the structure of formula IV: wherein, R 3, R 4, R 5, R 6 are each independently H, alkyl, C1~C4 alkenyl, alkynyl, C3∼C7 cycloalkyl, C3∼C7 cycloalkenyl, phenyl or benzyl, alternatively, R 5 and R 6 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group, alternatively, R 3 and R 4 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group. m, n are each independently 1, 2, 3, 4, 5 or 6, p is 1, 2 or 3. wherein, R 3, R 4, R 5, R 6 are each independently H, alkyl, C1~C4 alkenyl, alkynyl, C3∼C7 cycloalkyl, C3∼C7 cycloalkenyl, phenyl or benzyl, alternatively, R 5 and R 6 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group, alternatively, R 3 and R 4 together with their adjacent carbon atoms form a C3∼C7 cycloalkyl group, or together with their adjacent carbon atoms form a C3∼C7 cycloalkenyl group. m, n are each independently 1, 2, 3, 4, 5 or 6, p is 1, 2 or 3.