diff --git a/autoload/SpaceVim/layers/debug.vim b/autoload/SpaceVim/layers/debug.vim
index 1e3f6b34c..836b48f4f 100644
--- a/autoload/SpaceVim/layers/debug.vim
+++ b/autoload/SpaceVim/layers/debug.vim
@@ -11,12 +11,15 @@ function! SpaceVim#layers#debug#config() abort
   call SpaceVim#mapping#space#def('nnoremap', ['d', 'c'], 'VBGcontinue', 'Continue the execution', 1)
   call SpaceVim#mapping#space#def('nnoremap', ['d', 'o'], 'VBGstepOver', 'step over', 1)
   call SpaceVim#mapping#space#def('nnoremap', ['d', 'i'], 'VBGstepIn', 'step into functions', 1)
-  call SpaceVim#mapping#space#def('nnoremap', ['d', 'o'], 'VBGstepOut', 'step out of current function', 1)
+  call SpaceVim#mapping#space#def('nnoremap', ['d', 'O'], 'VBGstepOut', 'step out of current function', 1)
   call SpaceVim#mapping#space#def('nnoremap', ['d', 'k'], 'VBGkill', 'Terminates the debugger', 1)
   let g:_spacevim_mappings_space.d.e = {'name' : '+Evaluate/Execute'}
   call SpaceVim#mapping#space#def('nnoremap', ['d', 'e', 's'], 'VBGevalSelectedText', 'Evaluate and print the selected text', 1)
   call SpaceVim#mapping#space#def('nnoremap', ['d', 'e', 'e'], 'VBGevalWordUnderCursor', 'Evaluate the <cword> under the cursor', 1)
   call SpaceVim#mapping#space#def('nnoremap', ['d', 'e', 'S'], 'VBGexecuteSelectedText', 'Execute the selected text', 1)
+  call SpaceVim#mapping#space#def('nnoremap', ['d', '.'], 'call call('
+        \ . string(s:_function('s:buffer_transient_state')) . ', [])',
+        \ 'debug transient state', 1)
 endfunction
 
 function! SpaceVim#layers#debug#launching(ft) abort
@@ -30,3 +33,61 @@ function! SpaceVim#layers#debug#launching(ft) abort
     echohl None
   endif
 endfunction
+
+function! s:buffer_transient_state() abort
+    let state = SpaceVim#api#import('transient_state') 
+    call state.set_title('Debug Transient State')
+    call state.defind_keys(
+                \ {
+                \ 'layout' : 'vertical split',
+                \ 'left' : [
+                \ {
+                \ 'key' : 'o',
+                \ 'desc' : 'step over',
+                \ 'func' : '',
+                \ 'cmd' : 'VBGstepOver',
+                \ 'exit' : 0,
+                \ },
+                \ {
+                \ 'key' : 'i',
+                \ 'desc' : 'step into functions',
+                \ 'func' : '',
+                \ 'cmd' : 'VBGstepIn',
+                \ 'exit' : 0,
+                \ },
+                \ ],
+                \ 'right' : [
+                \ {
+                \ 'key' : 'O',
+                \ 'desc' : 'step out of current function',
+                \ 'func' : '',
+                \ 'cmd' : 'VBGstepOut',
+                \ 'exit' : 0,
+                \ },
+                \ {
+                \ 'key' : 'k',
+                \ 'desc' : 'Terminates the debugger',
+                \ 'func' : '',
+                \ 'cmd' : 'VBGkill',
+                \ 'exit' : 1,
+                \ },
+                \ ],
+                \ }
+          \ )
+    call state.open()
+endfunction
+
+" function() wrapper
+if v:version > 703 || v:version == 703 && has('patch1170')
+    function! s:_function(fstr) abort
+        return function(a:fstr)
+    endfunction
+else
+    function! s:_SID() abort
+        return matchstr(expand('<sfile>'), '<SNR>\zs\d\+\ze__SID$')
+    endfunction
+    let s:_s = '<SNR>' . s:_SID() . '_'
+    function! s:_function(fstr) abort
+        return function(substitute(a:fstr, 's:', s:_s, 'g'))
+    endfunction
+endif
diff --git a/docs/layers/debug.md b/docs/layers/debug.md
index ca6db7b73..5433e93b9 100644
--- a/docs/layers/debug.md
+++ b/docs/layers/debug.md
@@ -36,3 +36,9 @@ To use this configuration layer, add `call SpaceVim#layers#load('debug')` to you
 | `SPC d e e` | Evaluate the `<cword>` under the cursor  |
 | `SPC d e S` | Execute the selected text                |
 | `SPC d k`   | Terminates the debugger                  |
+
+**Debug Transient State**
+
+key bindings is too long? use `SPC d .` to open the debug transient state:
+
+![Debug Transient State](https://user-images.githubusercontent.com/13142418/33995923-16171792-e0a5-11e7-8a10-3624adcbba91.png)