Method for controlling a hybrid power train of a motor vehicle, comprising a primary electric machine for driving the motor vehicle, which is connected via a first inverter to a DC voltage bus of which the voltage is smoothed by a passive damping element, the hybrid power train further comprising a secondary electric machine which is capable of receiving the energy generated by a heat engine and transmitting it to said DC voltage bus via a second inverter regulating the voltage of said DC voltage bus; and an electric storage battery which is connected to the DC voltage bus by means of a controlled relay, in order to supply a DC voltage (V DC) to said DC voltage bus; the motor vehicle comprising a control element for the power train, suitable for implementing a prior step during which the opening of said controlled relay is controlled so as to isolate the battery from the DC voltage bus; and the method being suitable for implementing the following steps: - a step of predicting said rotation speed (Ω( t + h)) of the heat engine, after a predetermined time (h) corresponding to the delay in response of said heat engine; - a step of regulating the rotation speed (Ω( t)) of the heat engine on the basis of said prediction of said rotation speed (Ω( t + h)) of the heat engine; and when a torque request (C demand) greater than the instantaneous torque capacity of the heat engine is made by a user, then follows: - a step of comparing a target rotation speed (Ω*) of the heat engine with said predicted rotation speed (Ω( t + h)); - as long as said predicted rotation speed (Ω( t + h)) is lower than said target rotation speed (Ω*), then a target torque ( C ME ∗) of the primary electric machine of zero is set and a target torque ( C MTh ∗ t) of the heat engine corresponding to the maximum torque value ( C MThmax ∗) of said heat engine is set; and - when said predicted rotation speed (Ω( t + h)) is greater than or equal to said target rotation speed (Ω*), then a target torque ( C ME ∗) of the primary electric machine is set which is equal to the torque requested (C demand) by the user, while the torque of the heat engine is freely regulated by said regulation step. the hybrid power train further comprising a secondary electric machine which is capable of receiving the energy generated by a heat engine and transmitting it to said DC voltage bus via a second inverter regulating the voltage of said DC voltage bus; and an electric storage battery which is connected to the DC voltage bus by means of a controlled relay, in order to supply a DC voltage (V DC) to said DC voltage bus; the motor vehicle comprising a control element for the power train, suitable for implementing a prior step during which the opening of said controlled relay is controlled so as to isolate the battery from the DC voltage bus; and the method being suitable for implementing the following steps: - a step of predicting said rotation speed (Ω( t + h)) of the heat engine, after a predetermined time (h) corresponding to the delay in response of said heat engine; - a step of regulating the rotation speed (Ω( t)) of the heat engine on the basis of said prediction of said rotation speed (Ω( t + h)) of the heat engine; and - a step of predicting said rotation speed (Ω( t + h)) of the heat engine, after a predetermined time (h) corresponding to the delay in response of said heat engine; - a step of regulating the rotation speed (Ω( t)) of the heat engine on the basis of said prediction of said rotation speed (Ω( t + h)) of the heat engine; and when a torque request (C demand) greater than the instantaneous torque capacity of the heat engine is made by a user, then follows: - a step of comparing a target rotation speed (Ω*) of the heat engine with said predicted rotation speed (Ω( t + h)); - as long as said predicted rotation speed (Ω( t + h)) is lower than said target rotation speed (Ω*), then a target torque ( C ME ∗) of the primary electric machine of zero is set and a target torque ( C MTh ∗ t) of the heat engine corresponding to the maximum torque value ( C MThmax ∗) of said heat engine is set; and - when said predicted rotation speed (Ω( t + h)) is greater than or equal to said target rotation speed (Ω*), then a target torque ( C ME ∗) of the primary electric machine is set which is equal to the torque requested (C demand) by the user, while the torque of the heat engine is freely regulated by said regulation step. - a step of comparing a target rotation speed (Ω*) of the heat engine with said predicted rotation speed (Ω( t + h)); - as long as said predicted rotation speed (Ω( t + h)) is lower than said target rotation speed (Ω*), then a target torque ( C ME ∗) of the primary electric machine of zero is set and a target torque ( C MTh ∗ t) of the heat engine corresponding to the maximum torque value ( C MThmax ∗) of said heat engine is set; and - when said predicted rotation speed (Ω( t + h)) is greater than or equal to said target rotation speed (Ω*), then a target torque ( C ME ∗) of the primary electric machine is set which is equal to the torque requested (C demand) by the user, while the torque of the heat engine is freely regulated by said regulation step.