Photoplastical effect was discovered about 60 years ago. The first work was dedicated to crystalline semiconductors [1]. Photoplastical effect is manifested by hardening of illuminated materials [2], as well as by their softening [3]. Photoplastical effect depends on a number of factors such as: radiation power, temperature and wavelength. Study of spectral dependence of photoplasticity showed the maximum effect under samples illumination with wavelength close to the band gap value hν≥Eg [4]. Photoplasticity in chalcogenide films were studied in [5-7], where the effect was observed during samples illumination with wavelength comparable to band gap value. Nature of photoplastical effect is carried out definitively yet. The effect was attributed to thermal expansion of the film due to absorption of exciting light, as well as recombination of the photoexcited non-equilibrium electrons and holes. Investigation of photoplastical effect usually is performed under in-situ samples illumination during indentation [8, 9] as well as their indentation after illumination [10].figureFig.1. The experimental set-up for investigation of the photoplastical effect in chalcogenide glasses. In the present paper we report he experimental results on investigation of the photoplastical effect in amorphous As2Se3:Snx thin films. The amorphous As2Se3:Snx thin films with the thickness L ≈ 2μm were obtained by flash thermal deposition in vacuum of the initial bulk material on glass substrate held at the temperature Tsubstr = 100 oC. The mechanical properties of As2Se3:Snx was performed at NHT-SCM nanotester. In-situ illumination of samples was performed with green laser (λ = 532 nm) with power P = 50 mV/cm2. For change the direction of incident laser beam the optical glass prism was used. Maximum indentation load was 5mN, which allowed maximal penetration depth does not exceed 15% of film thickness. The experimental data are discussed and interpreted in framework of the existing theoretical models. [1] G. C. Kuczynski and R. F. Hochman, Phys. Rev. 108, 946 (1957); [2]. Yu. A. Osipyan and I. B. Savchenko, Zh. Eksp. Teor. Fiz. Pisma 7, 130 (1968); [3] A. B. Gerasimov, G. D. Chiradze, and N. G. Kutivadze, Semiconductors, 35, 72 (2001). [4] L. Carlsson and C. Svensson, J. Appl. Phys. 41, 1652 (1970); [5] A.Matsuda, H.Mizuno, T.Takayama, M.Saito and M. Ki-kuchi, Appl. Phys. Lett. 25, 411 (1974); [6] T. Igo, Y. Noguchi and H. Nagai, Appl. Phys. Lett. 25, 193 (1974); [7] H. Koseki and A. Odajima, Jap. J. Appl. Phys. 21, 424 (1982). [8] B. V. Deryagin, Yu. P. Toporov, K.I. Merzhanov, N. M Gal’vidis, I. N. Aleinikova, L. N. BurtaGaponovich, Sov. Phys. Solid State 16, 1155 (1974). [9] M. L. Trunov, A. G. Anchugin, Tech. Phys. Letters 18, 14 (1992); (b) M. L. Trunov, A. G. Anchugin, Tech. Phys. Letters. 18, 158 (1992); (c) M. L. Trunov, J. Non-Cryst. Solids 192-193, 431 (1995). [10] Y. Asahara and T. Izumitani, J. Non-Cryst. Solids 15, 343 (1974).