Retractable door device of a utility vehicle

A retractable door device of a utility vehicle comprising:

• a retractable door plate assembly having
• multiple door plates of different sizes that are arranged and concatenated in descending order of size, the concatenated door plates being extendable to form an overall long plate and retractable into the largest one of the door plates, and each one of the door plates having
• a space communicating with the spaces of the other door plates;
• and
• a first end and a second end, the first end of a smaller door plate of each two adjacent door plates limited and positioned in the second end of a larger door plate of said two adjacent door plates;
• at least one retractable assembly each having
• a retractor mounted in the largest door plate of the retractable door plate assembly;
• and
• a flexible elongated body mounted through the multiple door plates, and two ends of the flexible elongated body respectively connected to the retractor and the smallest one of the door plates, wherein the flexible elongated body can be retracted to and extracted from the retractor;
• a connecting assembly mounted through the first end of the largest door plate of the retractable door plate assembly;
• and
• a fastening assembly mounted through the second end of the smallest door plate of the retractable door plate assembly.