Trinity Cathedral represents the small chetyrekhstolpny krestovokupolny temple with one chapter and three low apses on a high podklet (the part of a podklet is closed by an occupation layer now). Walls of a cathedral are put from the correct blocks of a white stone, their thickness and massiveness is emphasized with deep perspective portals and narrow slit-like windows. Flat wide shovels give to facades three-part division and matter constructive pilasters. Smooth walls of a cathedral come to the end with keeled zakomara which arch laying leans on capitals of pilasters and is separated from the plane of walls by an additional ledge (for the first time in the Russian architecture thus the original treatment of classical order system is used). The keeled form закомар is repeated by two rows of kokoshniks at the basis of the drum of the dome which has kept an ancient shlemovidny form. As the only decoration of a cathedral serves the wide ornamental belt from three tapes of skillfully cut "wattled" pattern which decorates facades, altar apses and a drum of the dome.