An electric sanding handheld tool, comprising: a host body including a body and handgrip extended from the body, the body including a housing space inside; and a sanding assembly including an electric motor located in the housing space to output driving power through a transmission shaft and a circuit module to control operation of the electric motor, wherein the circuit module includes a control unit located in the body and coaxial with the electric motor and a power supply unit located in the handgrip and connected to the control unit to get working power from the external power to perform power transformation; one end of the transmission shaft where the control unit is located being defined as a first transmission portion and another end of the transmission shaft opposing the control unit being defined as a second transmission portion, the second transmission portion being coupled with a sanding element which is exposed outside the host body and driven by the transmission shaft to generate sanding motion; further comprising a cooling fan including a baseboard, an axial coupling portion located on the baseboard and coupled with the first transmission portion, a plurality of vanes located on the baseboard and centered about the axial coupling portion in a radial fashion, the body of the host body including at least one air outlet opened nearby to the vanes and at least one air inlet (113, 114) opened nearby to either of the control unit and the electric motor characterized in that the cooling fan is located on the first transmission portion and disposed between the control unit and the electric motor, wherein the cooling fan further comprises a plurality of connection ribs centered about the axial coupling portion and an airflow orifice located on the baseboard, wherein the airflow orifice is disposed around the axial coupling portion and defined by the vanes and the connection ribs, wherein the transmission shaft is driven by the control unit to synchronously drive the sanding element and the cooling fan through the first transmission portion and the second transmission portion so that the vanes spin to draw cold airflow through the air inlet (113, 114) to pass through the airflow orifice to dispel operation heat generated by the electric motor and the control unit through the air outlet. a host body including a body and handgrip extended from the body, the body including a housing space inside; and a sanding assembly including an electric motor located in the housing space to output driving power through a transmission shaft and a circuit module to control operation of the electric motor, wherein the circuit module includes a control unit located in the body and coaxial with the electric motor and a power supply unit located in the handgrip and connected to the control unit to get working power from the external power to perform power transformation; one end of the transmission shaft where the control unit is located being defined as a first transmission portion and another end of the transmission shaft opposing the control unit being defined as a second transmission portion, the second transmission portion being coupled with a sanding element which is exposed outside the host body and driven by the transmission shaft to generate sanding motion; further comprising a cooling fan including a baseboard, an axial coupling portion located on the baseboard and coupled with the first transmission portion, a plurality of vanes located on the baseboard and centered about the axial coupling portion in a radial fashion, the body of the host body including at least one air outlet opened nearby to the vanes and at least one air inlet (113, 114) opened nearby to either of the control unit and the electric motor characterized in that the cooling fan is located on the first transmission portion and disposed between the control unit and the electric motor, wherein the cooling fan further comprises a plurality of connection ribs centered about the axial coupling portion and an airflow orifice located on the baseboard, wherein the airflow orifice is disposed around the axial coupling portion and defined by the vanes and the connection ribs, wherein the transmission shaft is driven by the control unit to synchronously drive the sanding element and the cooling fan through the first transmission portion and the second transmission portion so that the vanes spin to draw cold airflow through the air inlet (113, 114) to pass through the airflow orifice to dispel operation heat generated by the electric motor and the control unit through the air outlet.