diff --git a/dreamplace/Params.py b/dreamplace/Params.py
index 2963a1c..d9c42ee 100644
--- a/dreamplace/Params.py
+++ b/dreamplace/Params.py
@@ -75,7 +75,7 @@ def getDefaultColumn(key, value):
         for key, value in self.params_dict.items():
             key_length_map.append(len(key))
             default_length_map.append(len(str(getDefaultColumn(key, value))))
-            description_length_map.append(len(value['description']))
+            description_length_map.append(len(value.get('description', '')))
             key_length = max(key_length, key_length_map[-1])
             default_length = max(default_length, default_length_map[-1])
             description_length = max(description_length, description_length_map[-1])
@@ -100,7 +100,7 @@ def getDefaultColumn(key, value):
                     " " * (key_length - key_length_map[count] + 1), 
                     str(getDefaultColumn(key, value)), 
                     " " * (default_length - default_length_map[count] + 1), 
-                    value['description'], 
+                    value.get('description', ''), 
                     " " * (description_length - description_length_map[count] + 1)
                     )
             count += 1
diff --git a/dreamplace/params.json b/dreamplace/params.json
index 8ea4d64..2c00f03 100644
--- a/dreamplace/params.json
+++ b/dreamplace/params.json
@@ -275,16 +275,16 @@
     "required" : "required for timing-driven mode"
     },
 "use_bb" : {
-    "descripton" : "whether use bb step", 
+    "description" : "whether use bb step", 
     "default" : 0
     }, 
 "macro_place_flag" : {
-        "descripton" : "whether enable macro placement", 
-        "default" : 0
+    "description" : "whether enable macro placement", 
+    "default" : 0
     },
 "two_stage_density_scaler" : {
-        "descripton" : "scale density weight after macro place", 
-        "default" : 1000
+    "description" : "scale density weight after macro place", 
+    "default" : 1000
     },
 "macro_halo_x": {
     "description": "horizontal halo around movable macros",