In this article, using analytical approach, the stress analysis of a long piezoelectric polymeric hollow cylinder reinforced with carbon nanotube (CNT) under combined magneto-thermo-electro-mechanical loading is investigated. Considering three combined loading conditions such as pressure-electric, pressure-electric magnetic and pressure-electric thermal, the governing equation of the problem is obtained. The rule of mixture and modified multiscale bridging model are used to predict effective properties of nanocomposite. The magneto-thermo-electro-mechanical stresses in hollow cylinder are discussed in detail. It can be concluded that increasing CNT volume fraction enhances strength of the nanocomposite cylinder. The results of this work could be useful in view of optimum design of the smart nanocomposite cylinder under magneto-thermo-electro-mechanical loadings and could also be as a reference for future related works.