This document proposes a secure tree-based search scheme for encrypted cloud data that supports multi-keyword ranked search and dynamic operations like deletion and insertion of documents. It combines the vector space model and TF-IDF model to construct a tree-based index and propose a "Greedy Depth-first Search" algorithm for efficient multi-keyword search. The scheme uses PEKS to encrypt the file index and queries while ensuring accurate relevance scoring between encrypted data. It aims to overcome security threats to keyword privacy in existing searchable encryption schemes and provide flexible dynamic operations on document collections in the cloud.