在你的情况下，***的办法是< p> 元素是继承：

所以在你的CSS文件，你应该使用，而不是内联样式：

  .parent-div {
 font-size：10pt; 
 color：red; 
} 

 .child-paragraph {
 font-size：12pt; 
 color：black; 
} 
 

I have a <div> element with a <p> element inside:

<div style="font-size:10pt; color:red;">
    This is my Parent Div.
    <p>This is my Child Paragraph.</p>
    My parent Div Ends Here.
</div>

How can I prevent my paragraph from inheriting the CSS properties set to the <div>?

In your case the best way is to just over right the styles that the <p> element is inheriting:

So in your CSS file, which you should be using instead of inline styles:

.parent-div {
    font-size: 10pt;
    color: red;
}

.child-paragraph {
    font-size: 12pt;
    color: black;
}