My presentation aims to describe the spirituality of Legion of Mary (LM) in the city of Kaifeng (Henan, China) from its foundation in 1947 until the expulsion of the last PIME Fathers in late 1953. The LM is a Catholic lay organization, founded in Ireland in 1921. Its members have a strong devotion to the Vergin and follow a strict set of rules, contained in the Handbook of the Legionary, written by the founder, Mr. Frank Duff. The theological base of the LM is Louis-Marie Grignion de Montfort's True Devotion to Mary. Since 1946, thanks to the Vatican internuncius, Msgr. Antonio Riberi, the organization became the most important form of Catholic Action in China. Despite its crucial role, the LM has been overlooked by scholars except for its events in Shanghai. Consulting the documentation at the PIME (Pontificio Istituto Missioni Estere) General Archive in Milan, I was able to trace the History of the LM in Kaifeng, the see of an archdiocese not so internationally exposed and lacking important cultural centres. There, the persecution against the LM began on Eastern 1951, when some of the most fervent legionaries (mainly young women) were incarcerated for defending their archbishop Msgr. Gaetano Pollio. Most of them were released after 6 months but for the following years they were forced to house arrest and went through different kinds of discrimination. Until 1953, despite the limitation to their personal freedom, they maintained an intense spiritual life, based on the rosary and different forms of self-mortification. They secretly exchanged messages with Fr. Giovanni Carbone, their spiritual director. These interesting correspondence is stored in the above-mentioned archive and describes how the legionaries' Marian devotion acquired both the militaristic connotations described in the LM Handbook, and the sense of total trust and abandonment to the Blessed Virgin, typical of the Montfortian spirituality.