Аннотация:The results of experimental investigations of acoustic nonlinear properties, - generation of the second harmonic, temperature dependence of the photoacoustic signal magnitude and a change in the velocity of longitudinal ultrasound,- in polycrystalline titanium are presented. Anomalous behavior of these properties is found in the range of parameters corresponding to the electronic topological transition (ETT) in a single-crystalline titanium. The measurements were performed by acoustic and photoacoustic methods on the polycrystalline titanium spesimen, that was grown by the iodine transport method.