In order to improve the quality of bimetal composite pipes by Pilger hot-rolling, the critical theory was put forward. For the process parameters such as feeding amount and rotation angle, the numerical simulation and experimental research were carried out on the Pilger hot-rolling process of 06Cr19Ni10/Q235 bimetal composite pipe. Then, the influences of feeding amount and rotation angle on bonding layer and ovality of bimetal composite pipe were studied, and the reliability of the critical theory was verified. The results show that the smaller rotation angle makes the stress on the bonding layer of bimetal composite pipe uniform, and the stress on the bonding layer is greater. When the ratio of rotation angle to feeding amount is close to the critical value 20°·mm-1, the maximum size of inclusion in the bonding layer of bimetal composite pipe is less than 8 μm, the ovality is 1.2 mm, and the formability is good. When the ratio is below the critical value 20°·mm-1, the maximum size of inclusions in the bonding layer of bimetal composite pipe is less than 6 μm, the avality is 1.1 mm, and cracking occurs locally. When the ratio is higher than the critical value 20°·mm-1, the maximum size of inclusions in the bonding layer of bimetal composite pipe reaches 25 μm, the avality is 11.8 mm, and cracking and earing occur at the same time.