Hi Masoud,
UColor is a regular retailer. Since they're dealing with their photography parts direct from their manufacturers, some of their products are indeed low-priced. Do note though that their listings are not updated (some are even added since 2012) so you may want to contact them directly before you purchase anything to make sure they're in stock. The site did not mention anything about wholesaling or drop shipping. However, they do accept safe payment methods such as PayPal or credit cards.
Although UColor is safe to deal with, making them as a regular supplier may not be suitable when it comes to stock availability. Also, the branded items they sell (like Sony, Nikon, Canon, etc.) needs licensing before you can re-sell them.
Again, we cannot guarantee the safety of any suppliers outside SaleHoo so it's best that you exercise caution when dealing with them.
Hope this helps.