The utility model discloses a single-cylinder plug type retractable boom and a boom position detection device thereof. The boom position detection device comprises a plurality of proximity switches which are arranged at the movable end of a retractable air cylinder and a plurality of sets of detection sheets which are matched with the proximity switches to work, wherein setting positions of all the proximity switches are different; each set of the detection sheet is arranged at the tail part of each retractable boom; in each set of the detection sheet, the setting position of any detection sheet corresponds to the setting position of one proximity switch; the setting positions of any two sets of the detection sheets are not completely same. With the adoption of the configuration, the detection of the retracting position of the retractable air cylinder is realized by different combinations of the detection sheets so that the quantity of the proximity switches can be reduced and the cost is reduced; the proximity switches are easy to array; the possibility that the proximity switches and the detection sheets are not matched well is reduced and the reliability of the boom position detection device is improved. The utility model further discloses a crane comprising the single-cylinder plug type retractable boom.