Nikkor 50mm 1.8d on DX body?

Hello to dslr expert out there,
right now i'm using nikon d5100, i like to know how this lens perform on dx body?

It performs well - it's a sharp, fast prime lens. On a crop sensor body, the field of view would be equivalent to a 75mm lens if you were using a full frame camera. If you have no prior experience of full frame (35mm) cameras, then the crop factor is totally irrelevant.

It will not autofocus on the D5100, as the D5100 has no focus motor in the camera body, so it would be manual focus only.

It makes a good portrait lens on your D5100 but only if you don't mind manually focusing it. Your D5100 requires Nikon's AF-S lenses for auto focus. The Nikon AF-S 50mm f1.8G might be a better choice although its more expensive.