The invention provides a method for enriching 
target gene fragments. The method comprises the following steps: (1) obtaining a partial or whole-length 
DNA (deoxyribonucleic acid) sample 
library containing a 
target gene; (2) obtaining 
a DNA probe 
library capable of hybridizing with the 
target gene; (3) hybridizing the 
DNA probe 
library and the 
DNA sample library; (4) separating a 
hybrid product obtained in the step (3), and releasing the target 
gene fragments subjected to hybridizing and enriching. According to the enrichment method, the invention further provides a method for detecting the 
gene structure 
mutation of the target 
gene. The method for detecting the gene structure 
mutation of the target gene comprises the following steps: (1) enriching the target gene fragments according to the method; (2) detecting the structure 
mutation of the target gene. The target gene fragments enriched by using the method can be used for next-generation sequencing technique to detect the gene structure mutation and comprise single-alkali base mutation, mRNA (
Messenger RNA) absence or increase, mRNA structure 
transversion and mRNA splicing change.