The invention discloses a grouting embedded pipe underground laying method in landslide dam diaphragm wall construction, which includes the following steps: forming slotted holes in the landslide damdiaphragm wall; downwards suspending embedded pipes through cross beams layer by layer to enable the layers of embedded pipes to be underground laid in the slotted holes layer by layer; when each layer of embedded pipes are underground laid, simultaneously positioning the embedded pipes in the layer of embedded pipes through an embedded pipe truss, downwards laying the embedded pipe truss alongwith the layer of embedded pipes to the slotted holes, wherein the embedded pipe truss includes a main frame for fixing the embedded pipes and a plurality of positioning frames fixedly connected withthe main frame, wherein the positioning frames extend along the width directions of the slotted holes respectively and contact with two side wall lines of the slotted holes, so as to avoid the condition that the embedded pipe truss downwards laid to the slotted holes, along with the embedded pipes strikes probe rocks on the side walls of the slotted holes, and cannot be continued to downwards laying. According to the method provided by the invention, the embedded pipes can be quickly and smoothly downwards laid while avoiding probe rocks under the landslide dam formation condition, and the laying success rate of the embedded pipes is increased, and the curtain grouting quality under the wall is guaranteed.