The present disclosure discloses a stator assembly and motor. The stator assembly comprises a stator core and a multi-branch rectangular conductor winding, an even number of stator slots are provided on an inner circumference of the stator core, and each of the stator slots is divided into multiple layers for accommodating rectangular conductors. The multi-branch rectangular conductor winding is provided in the stator slots, and the multi-branch rectangular conductor winding comprises B number of parallel branches, and B is an integer multiple of 4. The number of slots per phase per pole, Q, of the stator assembly is an odd number, and Q and B satisfy a relationship that both (Q+1)*2/B and (Q−1)*2/B are integers. In the stator assembly of the present disclosure, by way of the special winding connection design, there is no phase difference of magnetic fields between the parallel branches, and each parallel branch equally passes through each layer in the stator slots, which fundamentally inhibits the generation of circulating current between the parallel branches, suppresses the harmonics, and improves the efficiency of the motor.