两者均可用作副词，区别如下：
区别1 wide用作副词主要表示“张大”“睁大”到最大程度，侧重指物体从一边到另一边的距离（联系其形容词用法），通常与wide,apart等连用。如：
Open your mouth wide.把口张开。
The door was wide open.门敞开着。
He was standing with his feet wide apart.他站在那儿，两脚分开的距离很大。
区别2 widely则主要表示距离远、范围大、地域广等，通常连用过去分词。如：
He has traveled widely.他曾在广泛地区旅行。
The most widely distributed is the Hui people.分布最广的是回族。
Gas is now widely used for cooking and heating.现在普遍用煤气烧饭和取暖。
That the attempt to save her had failed soon became widely known.想救她而未救成，此事不久已尽人皆知。
有时也连用某些表示差异或变化的词语（如different,differing,range,vary等）。如：
The conversation ranged widely.谈话内容十分广泛。
Prices vary widely from shop to shop.各家商店价格悬殊很大。
Society is made up of people of widely differing abilities.社会是由能力迥异的人组成的。
区别3在wide awake（完全醒着）这一习语中，一般不用widely。如：
In bed he lay wide awake.他睡意全无地躺在床上。