The 18 inch suitcase can be carried on the plane. Size of 18 inch Trolley Case: 34cm * 44cm * 20cm. The volume of one article carried shall not exceed 20 * 40 * 55cm and the weight shall not exceed 5kg. The size of free carry on baggage on board shall not exceed 55cm × 40cm × 20cm, including handle and roller, that is, 21 inch box.
Other provisions on checked baggage in China civil aviation passenger baggage transport rules:
Article 39 passengers must check in their luggage with a valid ticket. The carrier shall indicate the number and weight of checked baggage on the passenger ticket and baggage ticket. Generally, the carrier shall collect the baggage when handling the check-in formalities on the day of flight departure; If group passengers have too much luggage or need to check in advance for other reasons, they can agree with passengers on the time and place to collect and transport.
The carrier shall hang a baggage tag on each baggage checked by the passenger and give the identification copy to the passenger. The self-care baggage agreed by the carrier shall be weighed together with the checked baggage and handed over to the passenger for self-care in the cabin, and the self-care baggage tag shall be hung on the baggage. Articles that do not belong to baggage shall be checked as goods and cannot be checked as baggage.