Dan Patterson, Thank you. I have few question, Hopefully this time i can clear my doubt,
1. I have 12 raster file, my aim is to plot all those raster into single pdf file using single legend, so i have to create 12 mxd for different raster or i have to create only 1 mxd for all raster? (In one mxd file, multi data frame can be added, its like draw a frame inside the frame , below i have attached one ArcGIS's snapshot of multilayer framing ).
Below is my working code that can produce pdf file from one mxd,
import arcpy mxd = arcpy.mapping.MapDocument(r"C:\Project\Project.mxd")
df = arcpy.mapping.ListDataFrames(mxd, "Transportation")[0]
arcpy.mapping.ExportToPDF(mxd, r"C:\Project\Output\ProjectDataFrame.pdf", df, df_export_width=1600, df_export_height=1200)
del mxd