Telescopic drain pipe

A telescopic drain pipe, comprising:

• a first pipe, comprising a first pipe body, wherein an outer wall of the first pipe body is provided with a positioning structure, and the positioning structure comprises at least two positioning grooves spaced apart in a length direction of the first pipe body;
• a second pipe, comprising a second pipe body sleeved over the first pipe body and slidable relative to the first pipe body in the length direction of the first pipe body;
• and
• an unlocking member, comprising an unlocking portion, wherein the unlocking portion is slidably mounted on an outer wall of the second pipe body, the unlocking portion is arranged corresponding to the positioning structure, the unlocking portion is connected to a buckle, the buckle is configured to engage with one of the at least two positioning grooves of the positioning structure to fix the second pipe body relative to the first pipe body, and the unlocking member is configured to drive the buckle to disengage from or engage into a corresponding positioning groove of the at least two positioning grooves,
• wherein the first pipe body is provided with a positioning projection in the respective positioning groove, the buckle comprises two buckling portions spaced apart on the unlocking portion, and when the buckle is inserted into a corresponding positioning groove of the at least two positioning grooves, the two buckling portions of the buckle press against the two opposite side walls of the corresponding positioning groove respectively, and the positioning projection is engaged between the two buckling portions of the buckle.