In the early 20th century, Troitsk had ten Orthodox churches and two chapels. The main church of the city was and remains the Holy Trinity Cathedral.

In 1743, on the day of the Holy Trinity, Orenburg Governor I.I. Neplyuev laid the foundation of a fortress dedicated to the Triune God-Creator, along with a church of the same name. The construction of the stone church began in 1754 and was completed in 1762. It was a single-altar five-domed church without a bell tower. In 1775, a warm wooden church with two altars was built nearby: on the lower floor in honor of the Dormition of the Mother of God, and on the upper floor, in honor of Saint Nicholas.

In 1823, due to its dilapidation, the Dormition Church was dismantled, and the altars were moved to the Trinity Church. After a fire in 1842, the church was closed for a year for restoration. During the reconstruction, the cathedral significantly increased in volume, the refectory was expanded, and a four-tier bell tower was added to the western side. A significant contribution to the improvement of the cathedral and other city churches was made by the honorary citizen of Troitsk, V.M. Pupychev.

The cathedral clergy participated in all significant events, such as the siege of the city by Pugachev's forces in 1774, fires, visits from spiritual and secular figures, including the heir to the throne, Nicholas Alexandrovich, in July 1891, and the procession with the miraculous Tabyn icon of the Mother of God. All new churches in the city were initially affiliated with the cathedral.

By 1913, there were three parish schools and three city schools operating at the cathedral, as well as one parish school. Among the notable priests were F. Galyakhovsky, S. Biryukov, D. Ozeretskovsky, G. Amanatsky, I. Ternov, P. Sementovsky, V. Lavrovsky, V. Petropavlovsky, A. Budrin, M. Menstrov, I. Ilyin, and G. Troitsky.

In 1918, an inventory of property was conducted in the cathedral, as in other churches in Russia, valuables were confiscated, and the building became municipal property as a "prayer house." In the 1920s, with the formation of the Chelyabinsk and Troitsk diocese, the Holy Trinity Church became the cathedral. In the 1930s, attempts were made to close it, and in May 1940, the city council executive committee requested district and regional authorities to close the cathedral. The empty building housed a warehouse, dormitories, and a gym.

In 1997, the church was returned to the believers, and on March 7, 1998, it was consecrated. In 2003, a group of restoration artists from the "Rosrestavratsiya" association of the Ministry of Culture of the Russian Federation began work on restoring the frescoes of the cathedral. Icon painter Y.S. Kadomtseva creates icons for the iconostasis.

In 2012, icon painters S.N. Kolomytsyev and V.B. Yartseva restored the dome painting, relying on preserved fragments of 19th-century painting.