The present invention relates to a method of controlling the combustion of a spark-ignition internal-combustion engine, in particular a supercharged engine, wherein the engine comprises at least one cylinder (12) with a combustion chamber (14), intake means (16), exhaust means (22) and fuel supply means (44) allowing a fuel mixture to be achieved in said combustion chamber.According to the invention, the method consists in: establishing, between a slow engine speed (Rf) and a low engine speed (Rb), a curve (C2) of the limit values (P2) of the load of cylinder (12) above which pre-ignition of the fuel mixture is favored, evaluating the effective cylinder load, heterogenizing, between the slow engine speed (Rf) and the low engine speed (Rb), the fuel mixture when the evaluated load value is close to the limit value (P2) established.