The invention discloses a guiding agent for controlling extension lower end height of a hydraulic fracturing crack. The guiding agent is prepared from the following components by weight percent: 20-40% of a dispersing agent, 10-20% of a curing agent, 20-40% of a bridging agent, 15-30% of a weighting agent, 2-6% of a softening agent and 2-6% of filler, wherein the dispersing agent is one or two ofglycidyl ether epoxy resin and glycidyl ester epoxy resin mixed at any ratio; the curing agent is quadrol, propane diamine or hexamethylenediamine; the bridging agent is one or two of polyethylene terephthalate and polybutylene terephthalate mixed at any ratio; the weighting agent is calcium carbonate or barite powder; the softening agent is a polyether nonionic surfactant with weight-average molecular weight within 500-1000; the filler is one or two of asbestos fiber and polypropylene fiber mixed at any ratio. After the guiding agent enters into a stratum, the guiding agent quickly settles tothe lower end of the crack and immerses into micro-crack and gap, so that the crack cannot continue extending to the lower end and the fracturing construction efficiency is increased.