The invention relates to a detection device for simultaneously measuring dissolved oxygen at different heights on a muddy water interface in situ. A detection probe is connected with a dissolved oxygen glimmering host computer; a probe used for detecting the dissolved oxygen can extend out of the detection probe; the detection device further comprises a detection box; the detection box is arranged on the muddy water interface; a plurality of vertical through water chambers and a plurality of slots horizontally penetrating the detection box are formed in the detection box; the slots are communicated with the water chambers; the detection device further comprises a plurality of insert sheets; probe slots are formed in the insert sheets; the outlines of the probe slots are adapted to the outline of the detection probe; the detection probe can be placed and fixed in the probe slots; the insert sheets can be inserted and fixed in the slots; the extending probe can be located in the different water chambers by adjusting the depth of the insert sheets inserted into the slots. The detection device provided by the invention has the advantages that the dissolved oxygen at different heights on the muddy water interface can be simultaneously measured, repeated tests can be avoided, the time is saved and the true distribution of the dissolved oxygen at different heights on a certain position of the muddy water interface at a certain time can be acquired.