The present application relates to an in-situ detection method for
coal seam gas extraction boreholes, the method comprising the following steps: after extending a gas extraction
pipe into an extraction borehole, the extraction borehole is sealed; a
wireless terminal and a probe are started, and the
wireless terminal is connected to the probe
pipe by
wireless communication; a three-way
pipe is connected to the pipe mouth of the gas extraction pipe, and the probe pipe is inserted into the gas extraction pipe by a push rod, and the push rod and the three-way pipe are sealed by a sealing sleeve to start gas extraction; the probe pipe synchronously and continuously measures the
methane concentration information and extraction negative pressure information of each measuring point in the extraction borehole; the
methane concentration information and extraction negative pressure information of each measuring point are received and viewed on the wireless terminal, and after fitting into a
methane concentration curve and an extraction negative
pressure curve, it is determined whether the sealed extraction borehole is leaking. The method of the present application detects parameters such as
gas concentration and extraction negative pressure at different parts of the extraction borehole in situ through a probe pipe, analyzes the distribution position of the
fracture zone, and then determines a reasonable sealing depth, and the determined sealing depth is reasonable and reliable.