Method for determining the reference air filling for calculating the ignition advance of a spark-ignition engine operating according to an operating cycle comprising an air intake phase into the engine in which: a1) we determine the quantity of air admitted (Qn) during the current operating cycle, a2) we determine the quantity of air admitted (Qn_i) during the operating cycle preceding the current operating cycle, a3) a variation in the quantity of intake air between two cycles is determined operating cycles (Qn, Qn-i) of the spark-ignition engine, from the difference in the quantities of air admitted to the current operating cycle and to the operating cycle preceding the current operating cycle (Qn, On-i), b) a transient regime of the spark-ignition engine is identified when this variation in the quantity of intake air is greater than a threshold value, characterized in that, when a transient regime is identified, (c) an intake air quantity (Qpred) is predicted for the air intake phase of the immediately upcoming operating cycle, this step comprising the steps of: c.1) determination of the quantity of air admitted (Qn) during the cycle of current operation, c.2) estimation of a variation of the quantity of intake air between the current operating cycle and the immediately upcoming operating cycle, c.3) prediction of the quantity of air admitted (Qpred) for the air intake phase of the upcoming operating cycle from the determined value of the air quantity admitted (Qn) during the current operating cycle and the variation of the estimated intake air quantity, d) this predicted intake air quantity (Qpred) is applied as the reference air filling (Qref) for the calculation of the ignition advance of the immediately upcoming operating cycle, and when a transient regime is not identified: - the quantity of intake air admitted (Qn) during the current operating cycle is applied as the reference air filling (Qref) for calculating the ignition advance for the upcoming operating cycle. a1) we determine the quantity of air admitted (Qn) during the current operating cycle, a2) we determine the quantity of air admitted (Qn_i) during the operating cycle preceding the current operating cycle, a3) a variation in the quantity of intake air between two cycles is determined operating cycles (Qn, Qn-i) of the spark-ignition engine, from the difference in the quantities of air admitted to the current operating cycle and to the operating cycle preceding the current operating cycle (Qn, On-i), b) a transient regime of the spark-ignition engine is identified when this variation in the quantity of intake air is greater than a threshold value, characterized in that, when a transient regime is identified, (c) an intake air quantity (Qpred) is predicted for the air intake phase of the immediately upcoming operating cycle, this step comprising the steps of: c.1) determination of the quantity of air admitted (Qn) during the cycle of current operation, c.2) estimation of a variation of the quantity of intake air between the current operating cycle and the immediately upcoming operating cycle, c.3) prediction of the quantity of air admitted (Qpred) for the air intake phase of the upcoming operating cycle from the determined value of the air quantity admitted (Qn) during the current operating cycle and the variation of the estimated intake air quantity, c.1) determination of the quantity of air admitted (Qn) during the cycle of current operation, c.2) estimation of a variation of the quantity of intake air between the current operating cycle and the immediately upcoming operating cycle, c.3) prediction of the quantity of air admitted (Qpred) for the air intake phase of the upcoming operating cycle from the determined value of the air quantity admitted (Qn) during the current operating cycle and the variation of the estimated intake air quantity, d) this predicted intake air quantity (Qpred) is applied as the reference air filling (Qref) for the calculation of the ignition advance of the immediately upcoming operating cycle, and when a transient regime is not identified: - the quantity of intake air admitted (Qn) during the current operating cycle is applied as the reference air filling (Qref) for calculating the ignition advance for the upcoming operating cycle. - the quantity of intake air admitted (Qn) during the current operating cycle is applied as the reference air filling (Qref) for calculating the ignition advance for the upcoming operating cycle.