The invention belongs to the field of high-polymer chemistry and materials science, and discloses polytriazole with intrinsic flame retardance and a preparing method and application thereof. Polytriazole has structures shown in the formula (I) or (II), wherein n represents an integer ranging from two to two hundreds, R1, R3 and R4 represent the same or different organic groups, R2 represents a connecting functional group, Fx represents fluorine atoms connected to a benzene ring, and x represents the number of F atoms and is an integer ranging from two to four. A two-functionality-degree or three-functionality-degree compound containing multi-fluorine aryl activated azido and a two-functionality-degree alkynyl compound are subjected to polymerization reaction in organic solvent or in a molten state to obtain polytriazole. Prepared polytriazole has excellent machinability, film-forming property, high heat stability, intrinsic flame retardance and aggregation-induced emission performance and can be used for chemical fluorescence detection and preparation of a flame retardant material.