Yes, of course we can change the background of UIPickerView Controller.
First of all create a UIView which will be used as background of UIPickerView and after we will add this view as subview of picker view, like this:

UIView *backgroundViewForPickerView = [[UIView alloc]
                                  initWithFrame:CGrectMake(0,0,150,60)];
[backgroundViewForPickerView setBackgroundColor: [UIColor colorWithPatternImage:
                                  [UIImage imageNamed:@"BackgroundView.png"]]];
[[[pickerView subViews] objectAtIndex:2] addSubview: backgroundViewForPickerView];

I hope it will be helpful for you. thank you.