diff --git a/src/utils/registerCustomElement.js b/src/utils/registerCustomElement.js
index b864f04..109a20b 100644
--- a/src/utils/registerCustomElement.js
+++ b/src/utils/registerCustomElement.js
@@ -7,6 +7,8 @@ export default function registerCustomElement(tag, options = {}) {
   function constructorCallback() {
     if (options.shadow === true && HTMLElement.prototype.attachShadow) {
       this.attachShadow({ mode: 'open' });
+    } else if (typeof options.shadow === 'object' && HTMLElement.prototype.attachShadow) {
+      this.attachShadow(options.shadow);
     }
     typeof options.constructorCallback === 'function' && options.constructorCallback.call(this);
   }
diff --git a/src/vue-custom-element.js b/src/vue-custom-element.js
index edec486..6421d14 100644
--- a/src/vue-custom-element.js
+++ b/src/vue-custom-element.js
@@ -74,7 +74,7 @@ function install(Vue) {
 
       observedAttributes: props.hyphenate,
 
-      shadow: !!options.shadow && !!HTMLElement.prototype.attachShadow
+      shadow: typeof options.shadow === 'object' ? options.shadow : !!options.shadow && !!HTMLElement.prototype.attachShadow,
     });
 
     return CustomElement;