The invention relates to a method for building a curtain of a deeply-buried ultra-thick solution gap 
fissure aquifer. The method aims at solving the problems that in existing mine deeply-buried 
aquifer curtain building, due to the low 
fissure exposure rate, the water interception rate is low, the inspection range of inspection 
drill holes is small and not flexible enough, and the effective drilling work amount proportion is low. The method comprises the steps that 1), inner and outer directional hole sets are formed in a curtain line, a 
drill hole grouting casing 
pipe enters a 
hard water-resisting layer at the top of a target 
aquifer, and 
branch holes of the directional hole sets are drilled in a segmented mode in the axial direction of the curtain along the target aquifer; 2), a grouting method for curtain building is adopted; 3), after grouting of all the directional hole sets is finished, the 
drill hole cross inspection grouting effect is inspected; 4), according to the aquifer 
exposure problem of the 
branch holes and the curtain quality inspection result of the inspection drill holes, vertical 
coring holes are formed in a targeted mode, and 
coring verification is carried out; 5), a ground hole transient electromagnetic method is used for probing the weak section of the curtain; and 6), the 
branch holes are used for carrying out supplementary grouting reinforcement on the weak section of the curtain according to the method in the step 2).