Compound cone single cone bit is a new type of single cone bit based on spherical single cone bit. Its unique rock breaking method can improve the bit efficiency. The field test found that the cutting teeth and diameter retaining teeth on the small end of the drill bit tooth wheel were seriously worn， and the cutting teeth and diameter retaining teeth at the large end of the tooth wheel were basically not worn， resulting in a decrease in the drilling speed of the entire drill bit. In order to find out the reasons for the uneven wear of the drill bit， the tooth load of each ring gear of the drill bit was tested by finite element analysis method， and the cutting trajectory shape of each ring gear tooth and the contact time between the tooth and the rock were analyzed. The results showed that the tooth load at the large end of the tooth wheel was greater than that at the small end of the tooth wheel， but the contact time between the teeth at the small end of the wheel and the rock was longer. Based on the analysis of tooth rock breaking time and tooth axial load， the wear of No.⑥ ring gear teeth should theoretically be minimal. The field test results show that not only the wear of the No.6 ring gear is small， but also the wear of the No.①，④ and ⑤ ring gear is smaller. The diameter retaining teeth on the side of the drill bit are seriously worn， and the wear of the ring gear No.⑦ and ⑧ is serious， it can be determined that the drill bit is tilted to the side of the well wall during drilling， resulting in serious wear of the cutting teeth and diameter retaining teeth on the side of the drill bit.