The invention discloses a longitudinal section line 
layout method and 
system, a terminal and a readable storage medium, and the method comprises the steps of obtaining the line information of a to-be-laid line, and constructing a longitudinal section line optimization model; obtaining a feasible region of 
station apron elevation search and a feasible region of line longitudinal section slope change point search based on the constraint conditions, and generating an initial 
layout result of a line longitudinal section, wherein the initial 
layout result is an initial value of a design variable; and based on the longitudinal section line optimization model, the feasible region of 
station apron elevation search, the feasible region of line longitudinal section slope change point search and the initial layout result of the line longitudinal section, optimizing by adopting an optimization 
algorithm to obtain a longitudinal section line layout result. According to the invention, the distribution of the gradient 
change points of the longitudinal section of the 
subway line and the collaborative optimization of the elevation of the 
station level are realized, and the 
coupling relation and dynamic characteristics of the gradient 
change points of the longitudinal section of the line and the elevation of the station level are considered, so that the scheme is more reasonable.