diff --git a/docs/design_docs/segcore/basic_types.md b/docs/design_docs/segcore/basic_types.md
index b2ee6ec8fd..5fa3b6388f 100644
--- a/docs/design_docs/segcore/basic_types.md
+++ b/docs/design_docs/segcore/basic_types.md
@@ -3,14 +3,14 @@
 - `Collection`: Data table containing multiple Segments
 - `Segment`: The memory structure of storing a piece of data which supports concurrent insertion, deletion, query, index loading, monitoring and statistics
 - `Schema`: Definition of collection data format, including
-    - `vector<FieldMeta>`: Order list of FieldMeta
-    - `isAutoId`: if set to True , default primary field is `RowId` and it is auto generated
-    - `primaryKey`: (when `isAutoId = False`) specify primary key field
+  - `vector<FieldMeta>`: Order list of FieldMeta
+  - `isAutoId`: if set to True , default primary field is `RowId` and it is auto generated
+  - `primaryKey`: (when `isAutoId = False`) specify primary key field
 - `FieldMeta`: field properties, including
-    - `DataType`: data type, including Int8...Int64, Float, Double, FloatVector, BinaryVector and String later
-    - `Dim`: (when dataType is vector) type vector dimension
-    - `metric_type`: (when dataType is vector type, optional) the metric type corresponding to this vector is related to the small batch index and can be empty
-    - `FieldName`: column name
-    - `FieldId`: unique number of the column
-    - (hidden) `FieldOffset`: which is the subscript of `vector<Field>` in the schema. The internal calculation of segcore is basically based on fieldoffset
+  - `DataType`: data type, including Int8...Int64, Float, Double, FloatVector, BinaryVector and String later
+  - `Dim`: (when dataType is vector) type vector dimension
+  - `metric_type`: (when dataType is vector type, optional) the metric type corresponding to this vector is related to the small batch index and can be empty
+  - `FieldName`: column name
+  - `FieldId`: unique number of the column
+  - (hidden) `FieldOffset`: which is the subscript of `vector<Field>` in the schema. The internal calculation of segcore is basically based on fieldoffset
 - `Span`: similar to STD::span. It supports vector type of data and can be implicitly converted to `SpanBase` for interface overwrite