The invention provides a multi-purpose telescopic loop antiskid mobile phone back shell, comprising a function support plate, a telescopic loop bar a, a telescopic loop bar b, a telescopic jam bar a and a telescopic jam bar b, a loop is formed by retracting and arching, a finger can hold the loop for a long time more easily after easily and freely sleeving in the loop, and meanwhile, a thumb can better operate a mobile phone or a tablet computer screen. In addition, the loop formed by the telescopic loop bar a, the telescopic loop bar b, the telescopic jam bar a and the telescopic jam bar b can be used as a supporting frame, thereby saving trouble and being convenient. The loop formed by the telescopic loop bar a, the telescopic loop bar b, the telescopic jam bar a and the telescopic jam bar b can being stretched in parallel, so as not to affect the call use, storage and beautiful appearance of the mobile phone, and a mounting support of the loop is integrally designed, embedded, mounted and fixed on the mobile phone back shell, a jacket or a tablet computer back cover, so that the loop is firmer and safer.