diff --git a/src/tree.c b/src/tree.c
index 7ea77aa..ee7073d 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -1339,7 +1339,7 @@ bool tree_rb_delete_fix(struct _tree* self, struct _tree_node* node)
             }
             else
             {
-                if(father->color = RBT_BLACK)
+                if(father->color == RBT_BLACK)
                 {
                     // case 4
                     // father is black, brother has no children
@@ -1388,7 +1388,7 @@ bool tree_rb_delete_fix(struct _tree* self, struct _tree_node* node)
             }
             else
             {
-                if(father->color = RBT_BLACK)
+                if(father->color == RBT_BLACK)
                 {
                     // case4
                     brother->color = RBT_RED;
@@ -1406,7 +1406,7 @@ bool tree_rb_delete_fix(struct _tree* self, struct _tree_node* node)
 
         if(tmp != NULL && tmp->parent == NULL)
         {
-            self->_root = node;
+            self->_root = tmp;
         }
     }
     
diff --git a/test/test_tree.c b/test/test_tree.c
index b165529..42f676d 100644
--- a/test/test_tree.c
+++ b/test/test_tree.c
@@ -155,6 +155,10 @@ static bool tree_rb_check_color(struct _tree *self, struct _tree_node* root, int
 static bool tree_rb_check(struct _tree* self)
 {
     assert(self != NULL);
+    if(self->_root == NULL)
+    {
+        return true;
+    }
 
     if(self->_root->color != RBT_BLACK)
     {