Method for controlling a turbocompressor, whereby a compressed air line (5) is connected to this turbocompressor (1) with a non-return valve (6) provided therein, characterised in that, when one or several process parameters exceed a predetermined limit, the rotational speed of the turbocompressor (1) will be reduced very suddenly to a predetermined minimum rotational speed and the above-mentioned non-return valve (6) will be closed and in that, after the above-mentioned reduction of the rotational speed, when one or several gear-down conditions are fulfilled, the rotational speed of the compressor (1) will be increased again and the non-return valve (6) will be opened.