diff --git a/readme.rst b/readme.rst
index 62f37b0..4b6cefe 100644
--- a/readme.rst
+++ b/readme.rst
@@ -2,11 +2,24 @@
 Trusted Firmware-M Tests
 ########################
 
-The Trusted Firmware-M Tests repo is meant to hold various tests for the
+The Trusted Firmware-M(TF-M) Tests repo is meant to hold various tests for the
 `Trusted Firmware-M`_.
-Currently it only contains the CMSIS RTX libraries, which is its the dependency.
-And the tests are within `test` folder in `Trusted Firmware-M`_ which will be
-moved to this repo gradually.
+The TF-M tests mainly focus on functionalities of various TF-M componentes such
+as the TF-M core and various secure partitions.
+
+There is also the `psa-arch-tests`_ suite which mainly focuses on the
+implementation compliance of the Platform Security Architecture(PSA).
+
+****************
+Folder Structure
+****************
+
+- app - The application code that executes the testing, including both the TF-M
+  tests and the `psa-arch-tests`_.
+- CMSIS - The libraries of RTX which is the Non-secure RTOS of the tests
+- test - The TF-M test codes including test framework, test suites and test
+  services
+
 
 ####################
 Feedback and support
@@ -15,5 +28,6 @@
 `TF-M mailing list <tf-m@lists.trustedfirmware.org>`__.
 
 .. _Trusted Firmware-M: https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/
+.. _psa-arch-tests: https://github.com/ARM-software/psa-arch-tests
 
 *Copyright (c) 2020, Arm Limited. All rights reserved.*