diff --git a/app/models/library.py b/app/models/library.py
new file mode 100644
index 0000000..ab722be
--- /dev/null
+++ b/app/models/library.py
@@ -0,0 +1,23 @@
+from sqlalchemy import Column, DateTime, String, ForeignKey, BigInteger
+from sqlalchemy.sql import func
+from .base import AutoID, Base
+
+class LibraryItem(Base, AutoID):
+    """工作区共享媒体/文件资源库"""
+    __tablename__ = "library_items"
+
+    workspace_id = Column(String(32), ForeignKey("workspaces.id", ondelete="CASCADE"), index=True)
+    # 自引用外键，支持无限级文件夹嵌套
+    parent_id = Column(String(32), ForeignKey("library_items.id", ondelete="CASCADE"), nullable=True, index=True)
+    
+    name = Column(String, nullable=False)
+    # 节点类型：'folder' (文件夹) 或 'file' (真实文件)
+    item_type = Column(String, default="file", nullable=False)
+
+    # --- 以下为真实文件（item_type='file'）的核心字段 ---
+    s3_key = Column(String, nullable=True)        # S3 中的 Object Key
+    file_size = Column(BigInteger, nullable=True)  # 文件大小（字节数 Bytes），用于统计容量占用
+    mime_type = Column(String, nullable=True)      # 媒体类型，例如 'image/jpeg', 'video/mp4', 'application/pdf'
+    
+    uploaded_by = Column(String(32), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
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diff --git a/app/models/project.py b/app/models/project.py
new file mode 100644
index 0000000..4a380da
--- /dev/null
+++ b/app/models/project.py
@@ -0,0 +1,20 @@
+from sqlalchemy import Column, DateTime, String, ForeignKey
+from sqlalchemy.sql import func
+from .base import AutoID, Base
+
+class ProjectNode(Base, AutoID):
+    """项目与文件夹的树状虚拟文件系统"""
+    __tablename__ = "project_nodes"
+
+    workspace_id = Column(String(32), ForeignKey("workspaces.id", ondelete="CASCADE"), index=True)
+    # 自引用外键：如果是根目录下的顶级节点，则 parent_id 为 Null
+    parent_id = Column(String(32), ForeignKey("project_nodes.id", ondelete="CASCADE"), nullable=True, index=True)
+    
+    name = Column(String, nullable=False)
+    # 节点类型：'folder' (文件夹) 或 'project' (代表具体文件的项目实体)
+    node_type = Column(String, default="project", nullable=False)
+    
+    # 如果是 project 节点，可以用这一列来存储其内容或配置快照（如 JSON 文本）
+    content = Column(String, nullable=True)
+
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
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