理解是逻辑层面，了解是经验层面。 你可以理解一种行为或者一件事，这意味着你知道这件事或者这种行为背后的原因已经因果逻辑。 你可以了解一个人或者一件事，这意味你足够熟悉这个人或者事物，你知道关于这个人或者事物足够多的信息所以你能够对这个人或事物有全面真实的评价。 理解（understand）concerns logic and 了解 is more empirical（了解 be translated as know about or learn about depending on whether you are talking about a fact or an action). You can 理解 a behavior or a thing, which means that you know that the causal factors or the reasons behind this event or this behavior. You can 了解 a person or a thing, which means you are sufficiently familiar with the person or the thing, and you know enough information about them so you can have a comprehensive and true evaluation of them.

above all, in different context they may have various meanings, you know that Chinese is high context, so normally: 了解refers to you've known about sth but you don't indeed know it on earth. 理解refers to you understand why it is

了解，有两个含义： 一、知道的清楚，例：我对他很了解。我很了解他。 二、打听、调查，例：这件事你去了解一下。 请看这个例子： 据我了解，你的意图仍然悬而未决。 这里的”了解“，用的是第二个意思，”调查”。如果我们换一下： 据我理解，你的意思仍然悬而未决。 这时意思就变成了，我得出的结论“你的意思仍然悬而未决”不是我经过调查得来的，而是我自己根据某些信息分析出来的。 理解和了解还有另一个更重要的区别： 我对他很了解。一般指“很清楚他的性格爱好，家庭情况，工作情况等等信息”。 我对他很理解。则是指”很清楚他的性格为什么是那样，他做了那件事是为了什么，等等“。

To put it simple, "了解” means to get to know something or someone. "理解” means to understand something or someone. They are pretty much the same thing，and so we need some more specific example sentences relating to your doubt to help you. So, what's your doubt?