An irregularly shaped distributed Bragg reflector (IDBR) for hetero-junction with intrinsic thin layer (HIT) solar cells is designed and fabricated according to the theory of multi-beam interference and the method of iteration. Four types of IDBRs ［S1（500 nm+800 nm）, S2(500 nm+900 nm), S3(500 nm+1000 nm), S4(500 nm+800 nm+1000 nm)］ are compared and optimized. The result shows that the structure of S3 with two pairs of α-Si(32 nm)/SiN(61.78 nm) and three pairs of α-SiH(64 nm)/SiN(123.57 nm) is the most suitable structure. With the help of plasma enhanced chemical vapor deposition (PECVD), five pairs of α-SiH/SiN distributed Bragg reflector (DBR) multi-layer films is deposited on the back surface of HIT solar cell. The testing result shows that the reflectivity of S3 is larger than 90% in the wavelength range of 730～1155 nm, and larger than 95% in the wavelength range of 750~1110 nm, which shows the great potential for improving the absorption of light in the wavelength range of 1000~1155 nm (infrared wavelength range), and thus enhance the efficiency of HIT solar cell.