Anode plasma electrolytic carburising is one of perspective high-speed methods of chemical heat treatment. However, this method has a lack. Anode dissolution of work pieces leads to rounding of its sharp edges that limits the use of this treatment for cutting tools. For elimination of this shortcoming it was offered to apply a carbon-copper coating on the work pieces where graphite is a source of carbon atoms, and copper prevents the fast dissolution of graphite in electrolyte. In this work, the anode carburising of low carbon steel from the carbon–copper coating is studied including structure of surface layer, its composition and hardness.   Researches are conducted on samples from steel 20 with diameter 12 mm and height 14 mm. The sample temperature is measured with the use of a digital multimeter with a thermocouple that was inserted into the sample approximately 1 mm to the low surface by drilling a hole. The surfaces of samples were coated by a layer of the graphite varnish "GRAPHIT 33" with thickness 100±25 microns before processing. The layer of copper was galvanic deposited on graphite; thickness of copper was is 75±20 microns. Heating of steel was carried out in water solution of ammonium nitrate with concentration of 2 mol/l. Carbonisation of samples was made at a temperature of 800 °C. This temperature was chosen because of the smaller oxidation rate of the anode surface [1] that allows one to keep a graphite layer on a sample surface more long. Processing time was 5, 10, 15 minutes.  Elemental EDX analysis and microhardness distribution in the surface layer of the treated samples are investigated. Microhardness measures confirm formation of carburized layer. The maximum thickness of the effective carburised layer and the highest value of microhardness are received on samples after processing within 10 minutes: 350±10 microns with the maximum surface superficial microhardness 321±16 HV (after cooling in electrolyte). Nonlinear dependence of the diffusive layer thickness on the processing time permits us to speak about change of the coating structure, in particular about exhaustion of a carbon covering. The data of EDX analysis confirms the change of the surface layer structure. Copper layer on the sample surface is not detected after 5 min treatment; the graphite layer collapses completely after 15 minutes of processing. The EDX analysis revealed that iron atoms migrates to the sample surface during treatment with formation of iron oxide FeO. Thus, the obtained results show that carbon diffusion from the coating to steel sample takes place with the formation of the oxide layer.   On the done work it is possible to draw the following conclusion: the increase in time of heating of samples over 10 minutes is inexpedient because of increasing degradation of a graphite coating and growth of the oxide iron layer.