A parallel concatenated coding structure, which can improve the performance of polar codes in finite‐length regime, is proposed. In the proposed structure, the encoder is built using two systematic polar codes (SPCs), and the decoder adopts iterative belief propagation decoding algorithm. Numerical results in the binary‐input additive white Gaussian noise channel indicate that the proposed coding scheme can improve BER performance of polar codes significantly. Specially, BER of the proposed coding scheme with length 192 is almost equal to that of original SPCs with length 256, when the code rate is 1/3.