The invention discloses a method for optimizing designs of an underground 
pipe network and landscape plantation by using a BIM technology, and belongs to the field of environment technologies. The method comprises the steps of step 1, establishment of an underground 
pipe network model, which specifically comprises establishing a three-dimensional 
visualization model for 
storm sewage, running water, fire fighting, 
electric power, 
weak current pipelines and inspection wells by Revit 
software; step 2, establishment of a landscape plantation model, which specifically comprises establishing a three-dimensional 
visualization model for landscape plants, roads and structures; step 3, 
model integration and rendering; step 4, model inspection; step 5, model adjustment; step 6, providing a construction drawing; step 7, disclosure of construction technologies; and step 8, auxiliary 
map making of complex parts. According to the method, the 
optimal design is performed depending on the three-dimensional 
visualization, 
roaming and 
collision detection functions of the BIM technology, thus the problem can be solved at the protocol stage, and smooth progress of the later construction is ensured.