In Angarsk, the first Orthodox community appeared in August 1991, and its first priest was Vladimir Kilin, who is still the rector of the cathedral today. Initially, there was no church in the city, but with great effort, a building was obtained for its placement. The church was arranged in the former 'October' club in the 4th settlement, and the first services began with the Feast of the Dormition of the Most Holy Theotokos, in honor of which the church was named 'Dormition'.

From the very beginning, it was clear that the building provided on the principle of 'take what you have' could not become a full-fledged church for a large city. In 1992, design work began on the construction of the Holy Trinity Church, and in 1995, on the Feast of the Trinity, the first stone was laid for its foundation. The construction of the Angarsk church lasted 10 years and was financed through donations. Every fourth ruble came from ordinary residents, while the main part of the funds was provided by local entrepreneurs. The Angarsk construction management, which was responsible for erecting the church, handed over the cathedral building to the state commission. On the morning of September 24, 2006, the great consecration took place in the Holy Trinity Church, and the first liturgy was held. The largest icon for the church, 'Annual Menaion', was painted by local artist Evgeniya Prokopenko. It includes one hundred and twenty images of the Theotokos on one large icon. The size of the iconostasis is one and a half by two meters, and it consists of fragments measuring ten by twenty centimeters.

The cathedral was finally completed and consecrated by Archbishop Vadim (Lazebny) of Irkutsk and Angarsk on September 24, 2006.

Next to the cathedral, there are plans for the development of a street that has already been named Trinity Street. Vladimir Kilin has been appointed as the protodeacon and rector of the Trinity Cathedral of Angarsk.

Currently, the temple houses the Department of Religious Education of the Irkutsk Diocese, as well as an Orthodox library and a Sunday school with a choir class for adults and children.

The church is executed in the best traditions of Russian Orthodox architecture, yet it is unique. The snow-white tented vault, seven gilded domes, and several chapels make it special. The variety of forms in Russian church architecture is reflected in the number of domes crowning the churches, which has symbolic significance. One dome symbolizes the One God, three, the Holy Trinity, five, Christ and the four evangelists, seven, the seven sacraments of the Church, nine, according to the number of angelic orders, thirteen, Christ and the twelve apostles. The color of the dome also has significance in church symbolism: gold symbolizes heavenly glory.