The invention discloses a titanium nitride atomic layer deposition device and a deposition method thereof. According to the deposition method thereof, segmented gradient heat-up heating is carried outon a source bottle outlet pipeline and a titanium precursor conveying pipeline, segmented gradient heat-down heating is carried out on a front-stage pipeline, an oxidant blowing pipeline is directlyconnected into a vacuum pump without passing through a chamber, during the ALD reaction, a preprocessing before the process is carried out through the operation that the flow ratio between an oxidizing agent and a titanium precursor vapor is improved, the chamber and the pipeline are vacuumized for multiple times, so that the generation of particles in the chamber, especially in the front-stage pipeline can be reduced, the maintenance period of the vacuum pump can be prolonged, and the service life can be prolonged; residuals of the precursor and the oxidizing agent on the wall of the pipelineand in the cavity can be effectively removed, the occurrence of unexpected reactions is reduced, and the impurity pollution is reduced; and purity of a thin film can be improved, and a complex gas processing system is prevented from being arranged.