The invention discloses a liquid pressure nozzle to solve the problems of insufficient mixing depth, large resistance and the like of an alkylation reactor using an existing static mixer, fiber membrane or mechanical stirrer for mixing and distributing liquid concentrated sulfuric acid and iso-butane. The liquid pressure nozzle comprises a main pipe (3), and an inner cavity (4) of the main pipe (3) comprises an upper cylindrical inner cavity and a lower inverted conical inner cavity, Two inlet pipes (1) are arranged on two opposite sides of the main pipe respectively, and an inlet pipe inner hole (2) of an outlet end of each inlet pipe is communicated with the cylindrical inner cavity along the tangential direction of the cylindrical inner cavity. A disturbed flow element (5) is arranged at the top end of the cylindrical inner cavity, a throat (6) is arranged between the bottom end of the inverted conical inner cavity and the top end of a conical nozzle outlet (7), and a disturbed flow groove (8) is formed in a conical surface of the nozzle outlet and surrounds the axis line of the main pipe. The liquid pressure nozzle is mainly used for mixing, atomizing and distributing the liquid concentrated sulfuric acid and the iso-butane in the alkylation reactor.