Abstract: The limitation of Point Dilution proposed by Drost is analyzed according to the actual situation in the borehole.It is also discussed how to measure the horizontal flow when vertical flow exists in the borehole.There are two kinds of groundwater regime:suction acquifer and gushing acquifer.For the suction acquifer,we can directly use general dilution theory to calculate the horizontal flow,and for the gushing acquifer,according to their position,some techniques are proposed.Thus it will enlarge the area to measure flows in dilution theory greatly.