In this simulation, R32 in the inner tube is heated by the water flowing from the outer tube to make it boil. CFD is used to simulate the boiling heat transfer of the inner spiral bellows with different numbers of vertical grooves. The results showed that compared with the smooth tube, the inner helix corrugated structure enhances the boiling heat transfer but increases the pressure drop of the inner tube. The surface heat transfer coefficient and the inner tube pressure increase to 147% and 221% of the smooth tube, respectively. With the increase of the number of vertical grooves, the surface heat transfer coefficient and the pressure drop of the inner tube first increase and then decrease. When the number of vertical grooves is 16, they reach the maximum value, which are 157% and 261% of the smooth tube respectively. In addition, by analyzing the relationship between enhanced boiling effect and pump loss of different number of vertical grooves, it was found that PEC obtained the maximum value （1.523） when the number of vertical grooves was 16. Therefore, the performance of spiral bellows in vertical grooves is the best when the number of vertical grooves is 16.