The invention discloses a motor body and an electric spindle using the same, which belong to the field of polishing machines. The provided body with improved cooling solves the problem of poor coolingeffect in the middle of the body. According to the main point of the technical scheme, the motor body is comprised; the motor body is provided with a shaft hole and a cavity which is communicated with the shaft hole and used for installing a stator and a rotor; a concave water tank is incised inward on the outer side wall of the motor body; the concave water tank is located in the middle of the motor body, and the concave water tank is separated by a partition; the outer side wall of the motor body is provided with a water inlet hole and a water outlet hole, and the water inlet hole and the water outlet hole are located on both sides of the partition; the water inlet hole and the water outlet hole are communicated with the concave water tank through a communication groove; the outer sidewall of the motor body is in interference fit with a stainless steel sleeve for sealing the concave water tank; and the stainless steel sleeve is provided with through holes communicated with the water inlet hole and the water outlet hole. The motor body provided by the invention is applicable to a polishing machine.