Is there a requirement for the size of the box when traveling to Dubai?

You mean the requirements of the airline. Every airline has different regulations on the size and weight of carry-on baggage and checked baggage. Which airline do you want to fly? Dubai is the headquarters of Emirates. If Emirates is selected, the specific provisions are as follows:

For hand luggage:

First class and business class passengers can carry two carry-on luggage: a briefcase plus a handbag or a clothing bag. The size of the briefcase shall not exceed 18 x 14 x 8 inches (45 x 35 x 20 cm); The size of the handbag shall not exceed 22 x 15 x 8 inches (55 x 38 x 20 cm); The thickness of the folded garment bag shall not exceed 8 inches (20 cm). The weight of each piece of luggage shall not exceed 7 kg (15 lb).

Economy class passengers can carry one carry-on baggage: for example, a handbag or a laptop bag, the size should not exceed 22 x 15 x 8 inches (55 x 38 x 20 cm) and the weight should not exceed 15 pounds (7 kg).

Remarks: For handbags, this refers to the travel box you asked, which generally does not exceed 22 inches.

Customers traveling with babies: In any cabin, you can take an extra piece of checked baggage, the size is not more than 22 x 15 x 8 inches (55x38 x 20cm), the weight is not more than 22 pounds (10kg), and the single piece is not more than 50 pounds (23kg). In addition, if the cabin space permits, passengers traveling with babies can also bring a baby basket or a fully foldable stroller into the cabin. If there is no extra space in the cabin to put baskets or trolleys, these items can only be treated as checked baggage. But if checked, these items are not included in the baggage allowance.

For checked baggage:

Different airlines and departure cities have different checked baggage allowances. What city did you take off from?