The invention relates to a modeling method of a motor in electromagnetic field-flow field-temperature field coupling calculation. The method comprises the following steps that (1) a finite element calculation model of the motor is established, and an electromagnetic field value is calculated; a rotor calculation domain is set into a multi-component fluid calculation domain, and a model calculation domain of air, a rotor conductor and a rotor iron core is established; (3) the value is calculated in the corresponding model calculation domain, and the velocity of movement is worked out; (4) a result which is worked out from the calculation of the electromagnetic field value and the calculation domain of each part of the multi-component fluid serves as load and is loaded into a temperature field to solve and calculate, and a temperature result is worked out. The method is adopted to set the rotor calculation domain into multi-component fluid; in such a manner, after a rotor part which is originally slid is equivalent into liquid, the rotor part can be processed and solved quickly and conveniently through a fluid control equation, so that not only is the heat loss of all parts in the motor calculated comprehensively and precisely, but also the calculation time and calculation complexity can be greatly reduced.